BUG: Dynamic Private UserControl Extender Events Do Not Show

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 6.0

SYMPTOMS

If you declare the variable using early-binding syntax when you dynamically add an instance of a private UserControl, you cannot see or use any of the control's extender properties or events. You are only able to see and use the raw properties and events of the control (that is, those declared by the control itself).

CAUSE

Visual Basic 6.0 allows developers to dynamically add ActiveX controls to a form at run time. Typically, a VBControlExtender variable is used for the dynamically-added control, which performs late binding on the control. However, if the type of the control is known at compile time, you can declare the variable using early binding syntax like the following:

   Dim WithEvents MyCtl As MyUserControl 

RESOLUTION

Declare the variable for your dynamically-added control as VBControlExtender, and Use the extender to access your control late-bound.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a new standard .exe project. Form1 is created by default.



2. From the Project menu, add a new UserControl to the project.



3. Add the following code to the User Control:

   
         Event Click()
   
         Private Sub UserControl_Click()
            RaiseEvent Click
         End Sub
   
         Public Property Get Color() As OLE_COLOR
            Color = UserControl.BackColor
         End Property
   
         Public Property Let Color(Value As OLE_COLOR)
            UserControl.BackColor = Value
         End Property
    




4. Close the User Control design window and open the code window for Form1.



5. Add the following code to the General Declarations section of Form1:

   
         Dim WithEvents MyCtl as UserControl1
    




6. Click on the Event list, and select MyCtl. You will only see the Click event. None of the extender events (for example, GotFocus, LostFocus, DragOver, and so forth) are available. Further, if you try to use any extender properties in code you will get an error. For Example:

   
          MyCtl.Visible = True 'This will cause a compile error.
    




7. To make the extender events available, add the following code to Form1:

   
         Dim WithEvents MyCtl As VBControlExtender
   
         Private Sub Form_Load()
            Set MyCtl = Controls.Add("Project1.UserControl1", "myctrl")
            MyCtl.Move 1, 1
            MyCtl.Visible = True
            MyCtl.Color = &HFF0000
         End Sub
   
         Private Sub MyCtl_ObjectEvent(Info As EventInfo)
            MsgBox "This control event was fired: " & Info.Name
         End Sub
    




8. Before you run the project, go to the Project menu and select Project1 Properties. Click the Make, and clear the "Remove information about unused ActiveX controls" check box.



9. Save and run the project.

REFERENCES

For additional information, please see the following articles in the Microsoft Knowledge Base:

Q190670 : HOWTO: Dynamically Add Controls to a Form with Visual Basic 6.0

Q190153 : INFO: Remove Information About Unused ActiveX Controls

Keywords : kbActiveX kbActivexEvents kbCtrlCreate kbVBp600bug kbGrpVB
Version : WINDOWS:6.0
Platform :
Issue type : kbbug