BUG: DocumentComplete Does Not Fire When WebBrowser Is Not Visible

When its Visible property is set to "False", the WebBrowser control (Shdocvw.dll) does not fire the DocumentComplete event and a document does not reach READYSTATE_COMPLETE state.

The best workaround for applications that rely on a hidden WebBrowser control is for you to position the control so that it draws its user interface off its container window. To do this, set the Left property of the control equal to the negative of its Width property. In multimonitor scenarios, negative values can be valid screen coordinates, so the Left property value must be set to coordinates that are outside the values returned by calling the EnumDisplayMonitors() method.

Alternately, if the WebBrowser user interface is not needed, the WinInet APIs can provide much of the same functionality.

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

Steps to Reproduce Behavior

1. Start a new Standard EXE project in Visual Basic. Form1 is created by default.
2. Add the Microsoft Internet Controls (Shdocvw.dll) to the project. To so, from the Project menu, click Components.
3. Add the following controls to Form1:

      Object                     Name                  Caption
      -------------------------------------------------------------------
   
      WebBrowser                 WebBrowser1            
      CheckBox                   chkVisible            Visible (value of 1 - checked)
      CommandButton              cmdNavigate           Navigate
      CommandButton              cmdReadyState         ReadyState
   
    
   					

4. Copy the following code into the Code window of Form1:

      Private Sub cmdNavigate_Click()
         WebBrowser1.Navigate2 "http://msdn.microsoft.com/workshop"
      End Sub
   
      Private Sub cmdReadyState_Click()
         MsgBox WebBrowser1.Document.ReadyState
      End Sub
   
      Private Sub chkVisible_Click()
         WebBrowser1.Visible = chkVisible.Value
      End Sub
   
      Private Sub WebBrowser1_DocumentComplete(ByVal pDisp As Object,
                                               URL As Variant)
         MsgBox "DocumentComplete!"
      End Sub
   
      Private Sub WebBrowser1_NavigateComplete2(ByVal pDisp As Object,
                                                URL As Variant)
         MsgBox "NavigateComplete2!"
      End Sub
   					

5. From the Run menu, click Start or press the F5 key to start the program.
6. Click the Navigate button. Notice that both the NavigateComplete2 and DocumentComplete events are fired.
7. Clear the Visible checkbox to hide the WebBrowser control. Click the Navigate button again. Notice that only the NavigateComplete2 event is fired. Using the ReadyState button, verify that the control's ReadyState has not reached READYSTATE_COMPLETE (4).
   
   When you click Navigate again, the same behavior occurs. The DocumentComplete event is only fired when the Visible checkbox is selected, making the WebBrowser control visible again. You can correct the behavior by replacing the chkVisible_Click handler with the following code:

      Private Sub chkVisible_Click()
          If chkVisible.Value Then
              WebBrowser1.Left = 120 ' or whatever the normal Left value is
          Else
              WebBrowser1.Left = -WebBrowser1.Width
          End If
      End Sub