FIX: Error 405: "Unable to Show Modal Form Within this Context" (184200)


The information in this article applies to:

  • Microsoft Visual Basic Learning Edition for Windows 5.0
  • Microsoft Visual Basic Learning Edition for Windows 6.0
  • Microsoft Visual Basic Professional Edition for Windows 5.0
  • Microsoft Visual Basic Professional Edition for Windows 6.0
  • Microsoft Visual Basic Enterprise Edition for Windows 5.0
  • Microsoft Visual Basic Enterprise Edition for Windows 6.0
This article was previously published under Q184200

SYMPTOMS

When opening a form from an ActiveX DLL, you may receive the following error:
Unable to show modal form within this context."

CAUSE

This error occurs when all of the following are true:
  • The computer is running Windows 95, Windows 98, or Windows Me.
  • The ActiveX DLL has been compiled.
  • The client application is in the Visual Basic IDE.
  • The client application form has a BorderStyle property set to Dialog.
  • The ActiveX DLL form has been previously opened.

RESOLUTION

Set the BorderStyle of the form in the client application to Fixed Single, and remove the Min and Max buttons from the form. This results in the form behaving in the same manner as a form with a Dialog BorderStyle.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available. This problem no longer occurs in Windows 2000.

MORE INFORMATION

Steps to Reproduce Behavior

  1. Create an ActiveX DLL in Visual Basic. Name the project "SrvDialog." Place the following code in Class1:
           Option Explicit
       Public Sub ShowDialog()
           Form2.Show 1
       End Sub
  2. Add a form to the project. Change the Name and Caption properties to "Form2." Place the following code on Form2:
           Option Explicit
       Private Sub Form_Click()
           Unload Me
       End Sub
  3. Compile the DLL.
  4. Create a Standard EXE project in Visual Basic. Form1 is created by default. Make a reference to SrvDialog.DLL.
  5. Change the BorderStyle property of Form1 to 3 (Fixed Dialog). Place a CommandButton on Form1, and place the following code on Form1:
           Option Explicit
       Private Sub Command1_Click()
       Dim x As New SrvDialog.Class1
          x.ShowDialog
          Set x = Nothing
       End Sub
  6. Run the client application. Click Command1.
  7. Click Form2 to unload that form.
  8. Click Command1 again and note that Error 405 occurs.
Modification Type:MajorLast Reviewed:5/12/2003
Keywords:kbBug kbDLL kbfix kbForms kbServer KB184200
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