Jalaj P. Jha Technical & Miscellaneous Ramblings

Working with menus in Visual Basic

Menus in Visual basic 6.0 are created using the Menu object defined in the VB Library. The menu created so are flat Win98 style menus and do not support icons. Further they cannot be created at runtime and require "Menu Editor", modification though can be made during runtime.

Click on "Menu Editor..." under Tools on main menubar. Menu editor is accessible only if a form is focussed.

Caption field is the string that is visible on the Menu. Adding an Ampersand (&) before a character makes that character the 'Hot Key".

Name field is the name for the menu item and should be unique for the form. An object with this name is visible in the Code section of VB alongwith a single event "Click".

Index field is useful if you want to create an array of menu items, in case of which more than one menu items will have the same Name with different Index value. This way the click event for the menu item will also recieve the Index value as parameter and actions will be performed accordingly.

Shortcut dropdown list allows you to specify a shortcut that will fire the event associated with the particular Menu item.

HelpContextID is useful if your Application help file handles Context sensitive help requests.

By default if a linked object or an embedded object is active the top level menus and their submenus are displayed on the toolbar. Setting the Negotiate position field determines the position i.e. (Left, right or middle) where the menu would be shown in this case (defualt - Not shown).

Check field determines if a check mark is displayed before the menu item or not. Enabled and Visible fields determine if the menu item is Enabled or not and that it is visible or not. All these fields can be manipulated at runtime.

WindowList field is useful on the MDIForm. If this field is checked, list of all the active MDI clild forms are shown as submenu under the item.

Pressing the right arrow button makes the menu item a submenu under the menu item that's above it in the list. Pressing the Left arrow key negates the effect. Pressing Up and down button moves the selected menu item up/down in the list.

Using the Menu Editor as described above you can create the Menu for use with your application. Now we will discuss three other important topics associated with Menus.

Creating Menu Seperators

The Menu seperators are implemented in VB6 by creating dummy Menu items with single hyphen "-" set as caption.

As required with all menu items these too need to have unique names and though you can never click them, the objects are visible in code window with the click events. To prevent unnecessary listings in the code window it is preferable that all seperators are created as array of a single menu item.

Creating Context Sensitive Menu

Context Sensitive Menus are around us since Windows 95 where right clicking on an object shows up a menu related to the object. This can be implemented in VB using the PopMenu method of the form object.

PopupMenu Menu As object, [Flags], [X], [Y], [DefaultMenu]

The first parameter is the menu, submenu of which is to be displayed as context sensitive menu. That is, whatever menu Items you need to display as context sensitive menu should be placed under a menu item which is passed to the PopupMenu method as parameter. This menu item can be invisible if not required elsewhere in application.

The second parameter, optional, is the flag which is one or combination of more of the flags mentioned below. First two applies by default.

Const vbPopupMenuLeftAlign = 0      ' Menu is aligned Left to the point where mouse was clicked
Const vbPopupMenuLeftButton = 0     ' Menu disappears if the Left mouse button is clicked anywhere outside the menu area
Const vbPopupMenuRightButton = 2    ' Menu disappears if the Right mouse button is clicked anywhere outside the menu area
Const vbPopupMenuCenterAlign = 4    ' Menu is aligned centrally about the point where mouse was clicked
Const vbPopupMenuRightAlign = 8     ' Menu is aligned Right to the point where mouse was clicked

The Third and Fourth parameters are the co-ordinates where menu is placed, this can be used if you want to manually specify the menu location.

The last parameter is the menu item which is to be marked as default by making the item bold.

Creating Dynamic Menu

Since the menus cannot be created during runtime, complete dynamic control over the menu is not available. However since VB6 allows Array of menu items using index property, this feature can be exploited to create some dynamism.

Say you want to make available the list of files recently accessed as menu items under "File" menu item, similar to what is available with MS Office Application and many others. The number of files can be anything say 10. How to do that?

Using the "Menu Editor" create a menu item say mnuFiles giving index value as 0. This will now treat the menuitem as array. Make with menu item hidden by unchecking it's visible property.

Now say your filenames are stored as a collection

Dim objFilenames As New Collection

objFilenames.Add "c:\filename1"
objFilenames.Add "c:\filename2"
objFilenames.Add "c:\filename3"
objFilenames.Add "c:\filename4"

To dynamically create a menu item for each of these file simply require to code as below

For ctr = 1 To objFilenames.Count
    Load mnuFiles(ctr)
    mnuFiles(ctr).Caption = objFilenames.Item(ctr)
    mnuFiles(ctr).Visible = True
Next

Here for each filename in the collection you have loaded a new menu item with a new index value, change the caption to show the file name and make it visible.

Similarly you can, if needed, can also add menu items to the top level. Unfortunately a dynamically created menu item cannot be programmed this way to contain submenus.

The click event for mnuFiles will now get Index as parameter which will help you perform desired action. I have simply shown a msgbox giving the file name.

Private Sub mnuFiles_Click(Index As Integer)

    MsgBox objFilenames.Item(Index)

End Sub