PRB: Error 743 Adding ActiveX Controls to Control Collection (191864)

SYMPTOMS

When dynamically adding a large number of ActiveX controls into a Form's Controls Collection, you receive the following:

"Error 743. Unable to create or activate a new instance of <control name>."

RESOLUTION

While this situation has been reported as a bug, this is an application design problem and the best solution is "Don't do this." If you have encountered this problem, you are probably using controls where you should be using objects. Consider using a Class, ActiveX DLL, or ActiveX EXE to create your objects. If you must use controls, consider using windowless controls as they are less resource-intensive.

Keep in mind that forms with hundreds of visible controls will be confusing for the end user. If the controls are not being displayed, then there is no reason to use a control. ActiveX controls have a great deal of "overhead" when compared to an object.

MORE INFORMATION

Steps to Reproduce Behavior

Start a new Standard EXE project in Visual Basic. Form1 is created by default.
Choose Add Project from the File menu to add an ActiveX Control project.
Place an instance of UserControl1 on Form1.
Place a CommandButton on Form1.

Add the following code to the module of Form1:

      Private Sub Command1_Click()
         Dim i As Integer
         On Error GoTo trap
         For i = 1 To 1000
            Me.Controls.Add "project2.usercontrol1", "control" & i
         Next
         Debug.Print "Finished"
         Exit Sub
         trap:
         If Err.Number = 743 Then
            Debug.Print "Error 743 loading control #" & i
         End If
      End Sub