MDI Interface
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Transcript of MDI Interface
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EXAMPLE 1:
The end result of Example 1 will be a form containing a menu with two top-level items, File and Help.
The File menu, shown below, will have the following level-two items below it: New, Open, Save, SaveAs, Print, and Exit. Note that separator bars appear above the Save, Print, and Exit items.
The Help menu contains just one level-two item below it, About.
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To build a menu for use with your VB program, you use the Menu Editor, which appears as an icon in thetoolbar of the VB IDE. It is the circled item in the screen shot below:
Alternatively, you can invoke the Menu Editor from the Tools menu item as shown below:
To build the menu described above, perform the following steps.
1. Start a new VB project and invoke the Menu Editor using either method shown above (click the MenuEditor toolbar icon or select the Menu Editor option from the Tools menu). The Menu Editorscreen appears, as shown below:
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2. For "Caption", type &File (by placing the ampersand to the left of the "F", we establish "F" as anaccess key for the File item it enables the user to drop down the File menu by keying "Alt+F" onthe keyboard in addition to clicking the "File" item with the mouse).
For "Name", type mnuFile.
Your Menu Editor screen should look like this:
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Click the Next button.
3. Click the "right-arrow" button (shown circled below). A ellipsis (...) will appear as the next item in the
menu list, indicating that this item is a level-two item (below "File").
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For "Caption", type &New; for "Name", type mnuNew, and for "Shortcut", select Ctrl+N. Byspecifying a shortcut, you allow the user to access the associated menu item by pressing that keycombination. So here, you are providing the user three ways of invoking the "New" function: (1)clicking File, then clicking New on the menu; (2) keying Alt+F,N (because we set up an accesskey for "N" by placing an ampersand to left of "N" in "New"); or (3) keying Ctrl+N. At this point,your Menu Editor screen should look like this:
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Click the Next button.
4. For "Caption", type &Open; for "Name", type mnuOpen, and for "Shortcut", select Ctrl+O. Your Menu
Editor screen should look like this:
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Click the Next button.
5. For "Caption", type - (a hyphen), and for "Name", type mnuFileBar1. A single hyphen as the Caption
for a menu item tells VB to create a separator bar at that location. Your Menu Editor screenshould look like this:
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Click the Next button.
6. For "Caption", type &Save; for "Name", type mnuSave, and for "Shortcut", select Ctrl+S. Your Menu
Editor screen should look like this:
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Click the Next button.
7. For "Caption", type Save &As ..., and for "Name", type mnuSaveAs. Your Menu Editor screen should
look like this:
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Click the Next button.
8. For "Caption", type -, and for "Name", type mnuFileBar2. Your Menu Editor screen should look like
this:
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Click the Next button.
9. For "Caption", type &Print;for "Name", type mnuPrint; and for "Shortcut", select Ctrl+P. Your Menu
Editor screen should look like this:
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Click the Next button.
10. For "Caption", type -; and for "Name", type mnuFileBar3. Your Menu Editor screen should look like
this:
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Click the Next button.
11. For "Caption", type E&xit, and for "Name", type mnuExit. Your Menu Editor screen should look like
this:
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Click the Next button.
12. Click the "left-arrow" button (shown circled below). The ellipsis (...) no longer appears, meaning we
are back to the top-level items.
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For "Caption", type &Help; and for "Name", type mnuHelp. Your Menu Editor screen should look like this:
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Click the Next button.
13. Click the "right-arrow" button to create a level-two item below "Help". For "Caption", type &About; andfor "Name", type mnuAbout. Your Menu Editor screen should look like this:
14. At this point, we are done creating our menu entries, so click the OK button. That will dismiss themenu editor and return focus to the VB IDE.
15. Back in the VB IDE, your form will now have a menu, based on what you have set up in the MenuEditor. If you click on a top-level menu item (File for example), the level-two menu will drop down:
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16. Click on the New menu item. The code window for the mnuFileNew_Click event opens, as shownbelow. Note: Click is the only event that a menu item can respond to.
In thePlace mnuFileNew_Click event, place the code you want to execute when the user clicks the Newmenu item. Since this is just a demo, we will place a simple MsgBox statement in the eventprocedure:
MsgBox "Code for 'New' goes here.", vbInformation, "Menu Demo"
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17. Code similar MsgBox statements for the Open, Save, Save As, and Print menu items:
Private Sub mnuFileOpen_Click()
MsgBox "Code for 'Open' goes here.", vbInformation, "Menu Demo"
End Sub
Private Sub mnuFileSave_Click()
MsgBox "Code for 'Save' goes here.", vbInformation, "Menu Demo"
End Sub
Private Sub mnuFileSaveAs_Click()
MsgBox "Code for 'Save As' goes here.", vbInformation, "Menu Demo"
End Sub
Private Sub mnuFilePrint_Click()
MsgBox "Code for 'Print' goes here.", vbInformation, "Menu Demo"
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End Sub
18. For the Exit menu item Click event, code the statement Unload Me.
Private Sub mnuFileExit_Click()
Unload Me
End Sub
19. For the About menu item Click event, code as shown below:
Private Sub mnuHelpAbout_Click()
MsgBox "Menu Demo" & vbCrLf _
& "Copyright " & Chr$(169) & " 2004 thevbprogrammer.com", , _
"About"
End Sub
20. Run the program. Note how the code executes when you click on the various menu items. Also testthe use of the access keys (e.g., Alt+F, N) and shortcut keys (e.g., Ctrl-O).
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21. Save the program and exit VB.
Download the project files for this examplehere.
EXAMPLE 2:
This example shows you how to create a popup menu (sometimes called a context menu or a right-click menu).
1. Start a new VB project and place a label on the form. Name the label lblTestText. Set the Caption toTest Text.
http://www.vb6.us/files/VBPrograms/Menus/MenuDemo.ziphttp://www.vb6.us/files/VBPrograms/Menus/MenuDemo.ziphttp://www.vb6.us/files/VBPrograms/Menus/MenuDemo.ziphttp://www.vb6.us/files/VBPrograms/Menus/MenuDemo.zip -
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2. Open the Menu Editor, and create a top-level item with a Caption value ofPopUpFormat and theName mnuPopuUpFormat. Also importantly uncheck the Visible checkbox (see the circled itembelow). In order for a menu to be a pop-up menu, it must be invisible.
3. Create the following level-two menu items below the PopUpFormat top-level menu. (When creatingthese level-two items, keep the Visible box checked.)
Caption Name
Bold mnuBoldItalic mnuItalicUnderline mnuUnderline- (hyphen) mnuFormatSepCancel mnuCancel
When done, your Menu Editor should look like this:
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4. Click OK to save your changes. Note: When you return to the IDE, you will NOT see this menu on theform (remember it's a pop-up menu, and it will only be visible when invoked through code).
5. Code the lblTestText_MouseDown event as shown below. Note that the Button parameter is testedforvbRightButton as is conventional, we only want to pop up the menu if the user right-clicks onthe label. If the user clicks the right mouse button, the PopupMenu statement is executed. It isthis statement that makes the pop-up menu appear.
Private Sub lblTestText_MouseDown(Button As Integer, _
Shift As Integer, _
X As Single, _
Y As Single)
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If Button = vbRightButton Then
PopupMenu mnuPopUpFormat, vbPopupMenuRightButton
End If
End Sub
The full syntax for the PopupMenu method, from MSDN, is:
object.PopupMenumenuname, flags,x, y, boldcommand
The PopupMenu method syntax has these parts:
Part Descriptionobject Optional. An object expression that evaluates to an object in the Applies To
list. Ifobjectis omitted, the form with the focus is assumed to be object.Menuname Required. The name of the pop-up menu to be displayed. The specified
menu must have at least one submenu.Flags Optional. A value or constant that specifies the location and behavior of a
pop-up menu, described as follows:
Constant (location) Value DescriptionvbPopupMenuLeftAlign 0 (Default) The left side of the
pop-up menu is located atx.vbPopupMenuCenterAlign 4 The pop-up menu is
centered atx.vbPopupMenuRightAlign 8 The right side of the pop-up
menu is located atx.
Constant (behavior) Value DescriptionvbPopupMenuLeftButton 0 (Default) An item on the pop-
up menu reacts to a mouseclick only when you use theleft mouse button.
vbPopupMenuRightButton 2 An item on the pop-up menureacts to a mouse click whenyou use either the right orthe left mouse button.
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Note: To specify both a "location" constant and a "behavior" constant, addthe two values together. For example:
PopupMenu MyMenu, vbPopupMenuRightAlign +vbPopupMenuRightButton
X Optional. Specifies the x-coordinate where the pop-up menu is displayed. Ifomitted, the mouse coordinate is used.
Y Optional. Specifies the y-coordinate where the pop-up menu is displayed. Ifomitted, the mouse coordinate is used.
boldcommand Optional. Specifies the name of a menu control in the pop-up menu todisplay its caption in bold text. If omitted, no controls in the pop-up menuappear in bold.
5. Code the mnuBold_Click event as shown below. Note that the Checked property of the menu item isused. When set to True, this causes a checkmark to appear to the left of the menu item. TheChecked property is typically used as a toggle.
Private Sub mnuBold_Click()
If mnuBold.Checked Then
lblTestText.FontBold = False
mnuBold.Checked = False
Else
lblTestText.FontBold = True
mnuBold.Checked = True
End If
End Sub
6. Code the mnuItalic_Click and mnuUnderline_Click events in a similar fashion as shown below.
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Private Sub mnuItalic_Click()
If mnuItalic.Checked Then
lblTestText.FontItalic = False
mnuItalic.Checked = False
Else
lblTestText.FontItalic = True
mnuItalic.Checked = True
End If
End Sub
Private Sub mnuUnderline_Click()
If mnuUnderline.Checked Then
lblTestText.FontUnderline = False
mnuUnderline.Checked = False
Else
lblTestText.FontUnderline = True
mnuUnderline.Checked = True
End If
End Sub
7. Run the program and check out the various options you have coded.
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8. Save the program and exit VB.
Download the project files for this examplehere.
NOTES:
If desired, you can have both a "regular" menu and as many pop-up menus as you want on the sameform. Any top-level menu that has its Visible box checked in the Menu Editor will appear at the top of theform in the menu bar you create. Any top-level menu that has its Visible box unchecked in the MenuEditor will NOT appear at the top of the form in the menu bar, but can be used as a pop-up menu invokedwith the PopupMenu method.
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Comments
Fri, 09/10/2010 - 06:57Anonymous (not verified)
How to change font size of menu
How to change font size of menu
reply
Sat, 08/14/2010 - 09:29 murtaza (not verified)
vb 6.0 problem
http://www.vb6.us/files/VBPrograms/Menus/PopupDemo.ziphttp://www.vb6.us/files/VBPrograms/Menus/PopupDemo.ziphttp://www.vb6.us/files/VBPrograms/Menus/PopupDemo.ziphttp://www.vb6.us/printable/node/296http://www.vb6.us/tutorials/working-menus-vb6#comment-4697http://www.vb6.us/comment/reply/296/4697http://www.vb6.us/tutorials/working-menus-vb6#comment-4509http://www.vb6.us/tutorials/working-menus-vb6#comment-4509http://www.vb6.us/comment/reply/296/4697http://www.vb6.us/tutorials/working-menus-vb6#comment-4697http://www.vb6.us/printable/node/296http://www.vb6.us/files/VBPrograms/Menus/PopupDemo.zip -
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hey guys out there. i am preparing an application where i need to make menus. i know i can
display menus through menu editor, and also i can open 'open dialogue box' through
commondialoguebox. but i don't no how to open a file. plz guide me..
reply
Fri, 08/20/2010 - 10:08fifth (not verified)
Resolve the problem of murtaza
go here this link:
http://www.vb6.us/tutorials/common-dialogs-vb-tutorial
there's a Open File tutorial using a common dailogs!
reply
Thu, 07/29/2010 - 05:43 shanavas (not verified)
Effective Tutorial
This is very much helpful for beginners
reply
Wed, 07/21/2010 - 10:27vaishnavi kulkarni (not verified)
query
gdf i have a query about this chapter is that if i want to create the menu in other indian language
like Marathi,Kannada then what are the steps to craete this or how i will get this type of menues.
reply
Sun, 07/11/2010 - 01:50 Anonymous (not verified)
thanks for nice tutorial...
thanks for nice tutorial...
reply
Sat, 06/19/2010 - 10:15 HaroldMcFaggiton (not verified)
yeah
http://www.vb6.us/comment/reply/296/4509http://www.vb6.us/tutorials/working-menus-vb6#comment-4571http://www.vb6.us/comment/reply/296/4571http://www.vb6.us/tutorials/working-menus-vb6#comment-4414http://www.vb6.us/comment/reply/296/4414http://www.vb6.us/tutorials/working-menus-vb6#comment-4375http://www.vb6.us/comment/reply/296/4375http://www.vb6.us/tutorials/working-menus-vb6#comment-4318http://www.vb6.us/comment/reply/296/4318http://www.vb6.us/tutorials/working-menus-vb6#comment-4209http://www.vb6.us/tutorials/working-menus-vb6#comment-4209http://www.vb6.us/comment/reply/296/4318http://www.vb6.us/tutorials/working-menus-vb6#comment-4318http://www.vb6.us/comment/reply/296/4375http://www.vb6.us/tutorials/working-menus-vb6#comment-4375http://www.vb6.us/comment/reply/296/4414http://www.vb6.us/tutorials/working-menus-vb6#comment-4414http://www.vb6.us/comment/reply/296/4571http://www.vb6.us/tutorials/working-menus-vb6#comment-4571http://www.vb6.us/comment/reply/296/4509 -
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Thanks for theh tut!
Is there an way to add it to an textbox wihout you'll get the standard context box with :
paste,check spelling and so...
thx
reply
Wed, 06/02/2010 - 23:44KittyA (not verified)
Popup Menu with MSHFlexGrid?
Hello All,
Is it possible to use this same code to bind the popup menu with a MSHFlexGrid?? It does not
seem to work!!! Is there anything else that i need to specify when trying to invoke the popupmenu with a MSHFlexGrid??
Please help me with this
Many thanks for an early reply
http://www.vb6.us/comment/reply/296/4209http://www.vb6.us/tutorials/working-menus-vb6#comment-4132http://www.vb6.us/tutorials/working-menus-vb6#comment-4132http://www.vb6.us/comment/reply/296/4209 -
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MDI Overview
This document introduces you to the concept of Multiple Document Interface (MDI) and how to create menus
within an MDI application. You will learn to create an MDI application in Microsoft Visual Studio .NET and learn
why you might want to use this type of interface. You will learn about child forms that are contained within the
MDI application, and learn to create shortcut, or context-sensitive, menus.
MDI is a popular interface because it allows you to have multiple documents (or forms) open in one application.
Examples of MDI applications include Microsoft Word, Microsoft Excel, Microsoft PowerPoint, and even the
Visual Studio integrated development environment itself. Each application consists of one (or more) parent
windows, each containing an MDI client areathe area where the child forms (or documents) will be displayed.
Code you write displays as many instances of each of the child forms that you want displayed, and each child
form can only be displayed within the confines of the parent windowthis means you can't drag the child
forms outside the MDI container. Figure 1 shows a basic MDI application in use.
Figure 1. Use MDI to open multiple windows and have them all contained within the parent area
Single Document Interface
Don't be misled: MDI is only one of several possible paradigms for creating a user interface. You can also create
applications that display just a single form. They're easier to create, in fact. Those applications are called Single
Document Interface (SDI) applications. Microsoft Windows Notepad is an SDI application, and you can only
open a single document at a time. (If you want multiple documents open, you simply run Notepad multipletimes.) You are under no obligation to create your applications using the MDI paradigm. Even if you have
multiple forms in your project, you can simply have each one as a stand-alone form, not contained by any
parent form.
Uses of MDI
You'll use MDI most often in applications where the user might like to have multiple forms or documents open
concurrently. Word processing applications (like Microsoft Word), spreadsheet applications (like Microsoft
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Excel), and project manager applications (like Microsoft Project) are all good candidates for MDI applications.
MDI is also handy when you have a large application, and you want to provide a simple mechanism for closing
all the child forms when the user exits the application.
Creating an MDI Parent Form
To create an MDI parent form, you can simply take one of your existing forms and set its IsMDIContainer
property to True. This form will now be able to contain other forms as child forms. You may have one or many
container forms within your application.
Tip Note the difference here between Visual Studio .NET and Microsoft Visual Basic 6.0 behavior. In Visual
Basic 6.0, you could only have a single MDI parent form per application, and you had to use the Project menu
to add that one special form. In Visual Studio .NET, you can turn any form into an MDI parent form by simply
modifying a property, and you can have as many MDI parent forms as you require within the same project.
You may have as many different child forms (the forms that remain contained within the parent form) as you
want in your project. A child form is nothing more than a regular form for which you dynamically set the
MdiParent property to refer to the MDI container form.
Note The user interface objects you've designed within the Visual Studio environment are really templates for
forms. That is, they don't actually become real Form objects until you instantiate them at run time. Therefore,
your project can contain as many different templates for MDI child forms as you like. You can instantiate and
then show as many instances of as many different templates as you need, while your applications are running.
Run-time Features of MDI Child Forms
At run time, the MDI parent form and the MDI child forms take on special features:
All child forms are displayed within the MDI parent's clientarea. The client area is the area below the
MDI parent's title bar, any menus, and any tool bars. Child forms can be moved and sized only within the MDI parent's client area.
Child forms can be minimized and their icon will be displayed within the parent's client area.
Child forms can be maximized within the parent's client area and the caption of the child form is
appended to the caption of the MDI form.
Windows automatically gives child forms that have their FormBorderStyle property set to a sizable
border a default size. This size is based on the size of the MDI parent's client area. You can override this
by setting the FormBorderStyle property of the child form to any of the fixed type of borders.
Child forms cannot be displayed modally.
The MDI form can be minimized and only one icon will be displayed on the desktop representing the
MDI form and all of its children.
If the MDI form is unloaded, all of the loaded children will also be unloaded.
Note The client area includes any usable area on the MDI form minus any toolbars or status bars that you may
have added to the MDI form.
Create an MDI Project
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In this section, you will walk through the steps of creating a simple MDI application using Visual Studio .NET. To
do this, you will create a new form that will be the MDI parent form. You will add some menus to this new form,
and then you will load the product form from a menu as a child form.
Create the MDI Parent Form
To create the MDI parent form
1. Open Visual Studio .NET
2. Create a new Windows application project.
3. Set the name of the project to MDI.sln.
4. Rename the form that is created automatically to frmMain.vb.
5. With the frmMain selected, set the form's IsMdiContainer property to True.
6. Set the WindowState property to Maximized.
That's all there is to it: you've created an MDI parent form.
Creating MenusYour main form will require menus so that you can perform actions such as opening child forms, copying and
pasting data, and arranging windows. Visual Studio .NET includes a new menu designer that makes creating
and modifying menus a snap.
To add menus to your MDI parent form
1. Double-click the MainMenu tool in the Toolbox window to add a new object named MainMenu1 to the
form tray.
Note Unlike the form designer in Visual Basic 6.0, the Visual Studio .NET form designer places
controls that don't have a user interface at run time into a special area on the form designer: the form"tray". They're out of the way, and don't get buried underneath other controls. This is a real
improvement!
2. At the top of the MDI parent form, click the box with Type Here in it and type &File.
Tip Just as in Visual Basic 6.0, inserting an ampersand (&) into a menu caption displays the caption
with an underscore under the following letter. Pressing Alt+ acts as a hotkey, activating
the menu item. One thing to note: if you're using Windows 2000 or later, it's possible that the hotkeys
won't show up underlined until you press the Alt key. This setting is buried in the Display applet within
Control Panel. In the Display Properties dialog box, check the Effects page: the Hide keyboard
navigation indicators until I use the Alt key option controls this behavior.
3. Press Enter to move to the next menu item and type &Products.
4. Press Enter to move to the next menu item and type a hyphen (-).
Tip Rather than using the "-" to indicate a divider in the menu, you can insert the next menu item
(Exit, in this case), and then right-click the new item. Select "Insert Separator" from the context menu,
and Visual Studio .NET will insert a separator above the current item for you.
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5. Press Enter and type E&xit.
You have now created the first drop-down menu on your main form. You should have something that looks like
Figure 2.
Figure 2. The menu designer allows you to type your menu structure in a WYSIWYG fashion
To the right of the File menu and at the same level, you'll see another small box with the text, Type Here. Clickit and type the following menu items by pressing Enter after each one.
&Edit
Cu&t
&Copy
&Paste
Once more to the right of the Edit menu and at the same level, add the following menu items in the same
manner.
&Window
&Cascade Tile &Horizontal
Tile &Vertical
&Arrange Icons
Creating Names for Each Menu
After creating all the menu items, you'll need to set the Name property for each. (Because you'll refer to the
name of each menu item from any code you write concerning that menu item, it's important to choose a name
you can understand from within your code.) Instead of clicking each menu item one at a time and then moving
over to the Properties window to set the Name property, Visual Studio provides a shortcut: Right-click an item
in the menu, then select Edit Names from the context menu. Now you can simply click each menu item and set
the name property directly on each menu. This is certainly quicker than using the Properties window toaccomplish the same task.
Use the following names for your menu items:
mnuFile
mnuFProducts
mnuFExit
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mnuEdit
mnuECut
mnuECopy
mnuEPaste
mnuWindow
mnuWCasade
mnuWHorizontal mnuWVertical
mnuWArrange
Test out your application: Press F5 and you should see your main MDI window appear with your menu system
in place.
Display a Child Form
To add the code that displays the child form, frmProducts, make sure the main form is open in Design view, and
on the File menu, double-click Products. Visual Studio .NET will create the stub of the menu item's Click event
handler for you. Modify the procedure so that it looks like the following:
CopyPrivate Sub mnuFProducts_Click( _
ByVal sender As System.Object, _ByVal e As System.EventArgs) Handles mnuFProducts.Click
Dim frm As New frmProducts()
frm.MdiParent = Me
frm.Show()
End Sub
This code declares a variable, frm, which refers to a new instance of the frmProducts form in the sample project.Then, you set the MdiParent property of the new form, indicating that its parent should be the current form
(using the Me keyword). Finally, the code calls the Show method of the child form, making it appear on the
screen.
Some interesting things to note:
Me is a built-in keyword in Visual Basic .NETjust as in Visual Basic 6.0, this keyword refers to the class
whose code is currently running. In this case, that's the MDI parent form, whose menu item you just
clicked.
You don't have to set the MdiParent property of the new child form. If you don't, the form will simply
load as a new normal form, outside the MDI parent. As a matter of fact, you can set the MDI parent to
be a different MDI container if you like. If you don't call the Show method, the child form won't ever display.
Differentiating Between Child Windows
You'll note that each instance of the Products form looks identical. You'll most likely need some way to
differentiate the windows. One alternative is to modify the caption of the window as you load each instance. In
the sample, you can create a static variable to contain a counter, increment that variable each time you open a
form, and then assign that value into the Text property of the form.
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To uniquely identify each child form
1. Modify the mnuFProducts_Click procedure so that it looks like this:
Copy
Private Sub mnuFProducts_Click( _
ByVal sender As System.Object, _
ByVal e As System.EventArgs) _Handles mnuFProducts.Click
Dim frm As frmProductsStatic intCount As Integer
frm = New frmProducts()
' Increment the caption counter.intCount += 1
' Set the caption to be unique.
frm.Text = frm.Text & " " & intCount.ToString()
frm.MdiParent = Me
frm.Show()End Sub
2. Run the project, create a few Products forms, and note that the caption of each form includes a
different number.
Note What's that Statickeyword? Using Static, rather than Dim, to declare a variable inside a
procedure creates a variable that maintains its value from one invocation of the procedure to the next.
When you declare a variable using Dim, that variable gets reinitialized each time the procedure is
called. When you use Static, the variable maintains its value. That's what you want, in this case
you
want intCount to maintain its value, so that it continues to increment each time you create a new
instance of frmProducts.
Child Menus in MDI Applications
What if a child form has its own set of menus? How do those menus interact with the menus of the parent
form? In previous versions of Visual Basic you really didn't have much control over the behaviorthe menus of
the currently active child simply replaced the menus of its parent. In Visual Studio .NET, however, you can
control how the menus interact, using the MergeOrder and MergeType properties of the individual menu
items.
The MergeOrder propertycontrols the relative position of the menu item when its menu structure gets merged
with the parent form's menus. The default value for this property is 0, indicating that this menu item will be
added at the end of the existing menu items. The MergeType property controls how the menu item behaves
when it has the same merge order as another menu item being merged. Table 1 shows a list of the possible
values you can assign to the MergeType property.
Table 1. The MergeType property allows you to specify what happens when menu items merge
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Value Description
Add The MenuItem is added to the collection of existing MenuItem objects in a merged menu.
(Default)
MergeItems All submenu items of this MenuItem are merged with those of existing MenuItem objects
at the same position in a merged menu.
Remove The MenuItem is not included in a merged menu.
Replace The MenuItem replaces an existing MenuItem at the same position in a merged menu.
By default, a menu item's MergeOrder property is set to 0. The MergeType property is set to Add by default.
This means that if you create a child form with a menu on it, the menu will be added at the end of the main
menu. Consider Figure 3, which shows a child form called from the parent form's main menu. This form has a
Maintenance menu on it (and the parent form does not). All of the items on the parent's main menu have their
MergeOrder properties set to 0 and this menu's MergeOrder property is set to 0, so this menu will be added
at the end of the main menu on the MDI parent form.
Figure 3. A child form that has menus will by default be added to the end of the main menu
To create the form in Figure 3
1. On the Project menu, click Add Windows Form.
2. Set the new form's name to frmChildWithMenus.vb.
3. Add a MainMenu control to this form.
4. Set the Name property for the MainMenu control to mnuMainMaint.
5. Add the following menus as shown in Table 2.
Table 2. Windows Form menus
Menu Name
&Maintenance mnuMaint
&Suppliers mnuMSuppliers
&Categories mnuMCategories
If you were to call this form exactly like you did the Products form in the previous section you will see that your
main form looks like Figure 4. You can see that by default, the menu is added to the end of this form.
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Figure 4. Menus are added to the end of the main menu by default
Call this form by adding a new menu item under the File menu:
1. Open frmMain.vb in Design view.
2. Click on the separator after the Products menu item and press the Insert key to add a new menu item.
3. Type Child form with Menus as the text of this new menu item.
4. Set the Name property of this new menu item to mnuFChild.
5. Double click this new menu item and modify its Click event handler so that it looks like this:
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Private Sub mnuFChildMenus_Click( _ByVal sender As System.Object, _ByVal e As System.EventArgs) _Handles mnuFChildMenus.Click
Dim frm As New frmChildWithMenus()frm.MdiParent = Mefrm.Show()
End Sub
Note If you wish to merge the Maintenance menu in between the Edit and Window menus, you
could set the MergeOrder property on the Edit menu item to 1, and the MergeOrder property on the
Window menu to a 2. Then on the Maintenance menu item on frmChildWithMenus, set the
MergeOrder property to 1 and leave the MergeType with its default value, Add. Taking these steps
will add the Maintenance menu after the menu on the main form with the same MergeOrder numberas it has (that is, after the Edit menu, but before the Window menu).
Working with MDI Child Forms
If you have multiple child forms open, you may want to have them arrange themselves, much as you can do in
Word or Excel, choosing options under the Window menu. Table 3 lists the available options when arranging
child windows.
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Table 3. Choose one of these values when arranging child windows
Menu Item Enumerated Value
Tile Horizontal MdlLayout.TileHorizontal
Tile Vertical MdiLayout.TileVertical
Cascade MdiLayout.Cascade
Arrange Icons MdiLayout.ArrangeIcons
Add some menus to your main form for each of these options:
1. Open frmMain.vb in Design view.
2. On the Window menu, double-click Cascade.
3. For the Cascade menu item, modify the Click event handler so that it looks like the following:
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Private Sub mnuWCascade_Click( _ByVal sender As System.Object, _
ByVal e As System.EventArgs) _Handles mnuWCascade.Click
Me.LayoutMdi(MdiLayout.Cascade)End Sub
On the Window menu, double-click each menu item and add the appropriate code.
Tip The LayoutMDI method replaces the Arrange method you may have used in Visual Basic 6.0.
What If There's No Active Child Form?
If there's no active child form, attempting to work with the ActiveMdiChild property of the parent form will
trigger a run-time error. To avoid this situation, you can check the value of the property in the Click event
handler for the Window menu item, and enable or disable the Center Child Form menu item accordingly. To
add this feature, follow these steps:
1. With frmMain open in Design view, press F7 to edit the form's code module.
2. Select mnuWindow from the Class Name combo box (the list on the top left of the editor window),
and then select Select from the Method Name combo box (the list on the right).
3. Modify the Select event handler, so that it looks like this:
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Private Sub mnuWindow_Popup( _
ByVal sender As Object, _ByVal e As System.EventArgs) _
Handles mnuWindow.PopupmnuWCenterChild.Enabled = _
Not (Me.ActiveMdiChild Is Nothing)
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End Sub
4. 4.Run the project, and verify that if you have child windows displayed, the Center Child Form menu
item is enabled. If there isn't a child form open, verify that the menu item is disabled.
How does this work? Here are some things to consider:
The Popup event occurs when you select a menu item that includes sub-items. (You can't use the Click
event, since that event doesn't occur for menu items that contain sub-items.)
The Is operator allows you to compare values to the built-in value Nothing. In this case, the
ActiveMdiChild property returns this special value if it doesn't refer to a form, and you must use the Is
operator to check for this. (The = operator checks values for equality: the Is operator checks references
to objects for equality.)
The syntax of the procedure may be confusing. The value in parentheses (Me, ActiveChild, Is,
Nothing) returns a Boolean value: it's either True or False. The Not operator toggles the returned
value to be the opposite Boolean value. The whole line of code assigns the return value from the
expression in parentheses to the Enabled property of the menu item. In this case, if it's not true that
the ActiveChild is Nothing, you'll enable the menu item. If it's True, you'll disable the menu item.
Tracking Child Windows
Visual Basic .NET will keep track of all child forms that you create, and it's easy to create a window list menu to
manage the child windows. If you wish to see a list of all of the child forms and be able to give a specific child
form focus, follow these steps:
1. Load frmMain in Design view.
2. Select frmMain's Window menu.
3. In the Properties window, set the MdiList to True.
4. Run the project, open a couple of Products forms, and then click the Window drop-down menu. You
should see each instance of the Product form that you opened displayed in the window list.
Creating Shortcut Menus
In most modern Windows applications, you can click the right mouse button and see a context-sensitive, or
shortcut (pop-up), menu. These menus give you the ability to perform actions based on the current context
that is, changing depending on the current situation.
Visual Studio provides the ContextMenu control, making it just as easy to create context menus as it was to
create main menus. Once you've dropped one of these controls on your form (it will appear in the tray area, just
like the MainMenu control did), you can edit the menu items to be displayed by this context menu.
Note The design of your context menu won't display on the form until you've clicked the ContextMenucontrol. This makes it possible for one form to contain both MainMenu and ContextMenu controls.
Tip You can place as many ContextMenu controls as you need on your forms.
To add a context menu to the Products form:
1. Open frmProducts in Design view.
2. In the Toolbox, find the ContextMenu control.
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3. Double-click this control to add it to the tray area of the form.
4. Click the ContextMenu control to give it focus.
5. Change the Name property to cmnuProdID.
6. Add the menu items (shown in Table 4) to this control, and set the Name properties as shown. When
you add to a context menu, you start with the first menu item under the top-level menu. Figure 5
shows the finished context menu.
Table 4. Context menu items
Menu Name
&Lookup mnuPLookUp
&Copy mnuPCopy
&Paste mnuPPaste
Figure 5. When adding items to the ContextMenu control, create a top-level item that won't
ever be displayed as the parent for your items
7. Click the Product ID text box.
8. In the Properties window, set the ContextMenu property to the ContextMenu control you just
created, cmnuProdID.
9. Run the project. On the File menu, click Products to create a child form, and righ-click on the Product
ID text box to see the context menu appear.
If you were completing this form, you could now add code to respond to the Click events on each of these
menus.
Manipulating Menus at Run Time
You may need to modify the behavior of menu items while your application is running. In this section, you'll see
how to check and uncheck, and add and remove menu items programmatically.
To set up for the following sections, you will need to add three new menu items under the File menu on your
MDI form.
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1. Open frmMain.vb in Design view.
2. Click the File menu to display its sub-items.
3. Add three menu items, as described in Table 5.
Table 5. File menu items
Menu Name
&Add Menus mnuFAddMenus
&Remove Menus mnuFRemoveMenus
&Add &New Menu mnuFAddNew
Checking and Unchecking Menu Items
Visually selecting a menu item programmatically is easy: simply set the menu item's Checked property to True
or False, as necessary. For example, you might want to indicate that you've added new menu items by adding a
check to the Add Menus item, and remove it once you've removed the items. You'll add and remove the menu
items in the next section, but for now, add and remove the check by following these steps:
1. On the File menu, double-click Add Menus to view the Click event procedure.
2. Modify the event procedure, so that it looks like this:
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Private Sub mnuFAddMenus_Click( _
ByVal sender As System.Object, _ByVal e As System.EventArgs) _
Handles mnuFAddMenus.Click
If Not mnuFAddMenus.Checked ThenmnuFAddMenus.Checked = True
End If
End Sub
3. To repeat the previous two steps, on the File menu, double-click Remove Menus and modify its Click
event procedure so that it looks like this:
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Private Sub mnuFRemoveMenus_Click( _
ByVal sender As System.Object, _
ByVal e As System.EventArgs) _Handles mnuFRemoveMenus.Click
If mnuFAddMenus.Checked Then
mnuFAddMenus.Checked = FalseEnd If
End Sub
4. Run the project, and on the File menu, double-click Add Menus. Verify that you see a check next to
the item. To repeat, on the File menu, click Remove Menus to verify that the check has been removed.
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Adding and Removing Menus
Windows Forms allows you to add and remove menus programmatically at run time. Using the Add and
Remove (or RemoveAt) methods of the MenuItems collection, you can create new menus at run time, and
delete any menu items.
Note In Visual Basic 6.0, you could only delete menu items that you created dynamically, at run time. That is,
you couldn't delete static menu items. In Visual Studio .NET, you can delete any menu item.
Adding Menus ProgrammaticallyTo add a menu item, call the Add method of a particular menu item. For example, you might want to add two
new menu items on the File menu. To do this, follow these steps:
1. On the on the File menu, double-click Add Menus to view its Click event handler.
2. Modify the event procedure so that it looks like this:
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Private Sub mnuFAddMenus_Click( _
ByVal sender As System.Object, _ByVal e As System.EventArgs) _
Handles mnuFAddMenus.Click
If Not mnuFAddMenus.Checked ThenmnuFAddMenus.Checked = True
' Adds these menus to the end of the File menuWith mnuFile.MenuItems
.Add("New Menu 1")
.Add("New Menu 2")
End With
End IfEnd Sub
Each menu item contained within the MainMenu (or ContextMenu) control is itself a MenuItem object, and
just as with any other object, you refer to the menu items using the Name property you assigned to each. If a
menu item contains other menu items (as each top-level menu item does), you can use its MenuItems property
to refer to the collection of menu items it contains. In this case, you called the Add method of a MenuItem
object (mnuFile) to add menu items to the collection of items. (In this example, mnuFile was the name you
assigned to the File menu item.)
Removing Menus ProgrammaticallyTo remove menu items programmatically, you can either call the MenuItem collection's Remove or RemoveAt
method. Remove requires you to provide a MenuItem object; if you instead want to remove items by their
position within the menu, call the RemoveAt method.
In this example, the simplest way to remove the menu items you created in the previous steps is to specify their
position within the menu. You'll call the RemoveAt method to do the work. Because menu items are numbered
starting at 0 (as are all collections and arrays in Visual Basic .NET), you need to take that into account when
removing menu items.
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To handle removing the two menu items you've just added, modify the Click event procedure for the Remove
Menus items on the File menu, so that the procedure looks like this:
CopyPrivate Sub mnuFRemoveMenus_Click( _
ByVal sender As System.Object, _
ByVal e As System.EventArgs) _Handles mnuFRemoveMenus.Click
If mnuFAddMenus.Checked Then
With mnuFile.MenuItems
' Remove the last two items.RemoveAt(.Count - 1)
.RemoveAt(.Count - 1)End WithmnuFAddMenus.Checked = False
End If
End Sub
Run the project to verify that choosing the Add and Remove Menus menu items correctly adds and removes
the two extra items.
Using Menu Groups
When you add a check to a menu item, you're indicating the state of that menu itemit's either selected, or it's
not. Normal checked menus work individually, and are independent of other menu items.
You may have a need to treat a group of menu items as a dependent set. In this case, selecting one item from
the group forces all the other items in the group to be deselected. Although Visual Studio .NET doesn't provide
a way to make this happen for you, it does supply the RadioCheckproperty of menu items that at least
provides a visual indication. Rather than seeing a normal check, menu items with their RadioCheckproperty set
to True display a dot when they're selected. It's still up to your code to deselect all the other items in your
menu group, once the user selects a menu item.
To demonstrate this behavior, modify properties and add code so that the four window management menu
items (Cascade, Tile Horizontal, Tile Vertical, Arrange Icons) work as a group. To do that, follow these steps:
1. With frmMain open in Design view, select the Window>Center Child Form menu item.
2. Right-click, and on the shortcut menu, click Insert Separator, which inserts a separator item above the
selected item.
3. Click on the Window>Cascade menu item, then at the same time, press Ctrl and click the other four
window management items on the menu, selecting all four.
4. In the Properties window, set the RadioCheckproperty for the four selected menu items to True.
5. Add the following procedure to the frmMain class:
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Private Sub RadioCheck_Click( _
ByVal sender As System.Object, _ByVal e As System.EventArgs) _Handles mnuWArrange.Click, mnuWCascade.Click, _mnuWHorizontal.Click, mnuWVertical.Click
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mnuWArrange.Checked = False
mnuWCascade.Checked = FalsemnuWHorizontal.Checked = FalsemnuWVertical.Checked = FalseCType(sender, MenuItem).Checked = True
End Sub
6. Run the project, create some Product forms, and use the Window menu items to arrange the children.
As you use the Cascade, Tile Horizontal, and other menu items, you should see a circle next to the
most recently selected item. Figure 6 shows the results of adding this new feature.
Figure 6. Setting a menu item's RadioCheck property to True shows a dot, rather than a check,
next to selected items
How Did the Code Work?
It may seem odd that you managed to add new functionality to four menu items without modifying their event
procedures at all. This example took advantage of a new feature in Visual Basic .NETyou can hook up as many
event handlers to a specific event as you need, using the Handles clause on a procedure. Here, you provided a
new procedure (RadioCheck_Click) that handles Click events for each of the four menu items you want to have
work together.
Here are the important issues:
The procedure you want to call must match the procedure signature of the standard Click event for
menu items. That is, it must receive two parameters (one as System.Object, the other as
System.EventArgs) and return nothing at all. (It must be a Sub, in other words.)
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