BUG: DDE Paste Link with Word Fails to Update Using LinkSend

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, versions 5.0, 6.0
• Microsoft Word 97 for Windows

SYMPTOMS

When you use DDE (Dynamic Data Exchange) to create a Paste link between a Visual Basic Picture Box and a Word document when using the LinkSend method, the Word document will only update with the first LinkSend method call. Subsequent LinkSend calls will not update the pasted link within the Word document.

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 in Visual Basic. Form1 is created by default.



2. Change the Application Title in the Project Properties dialog to "DDEDEMO."



3. Add three CommandButtons and a PictureBox to Form1 with the following properties:

   
      Control             Name              Caption
      ------------------------------------------------
   
      CommandButton1     cmdClose           CLOSE
      CommandButton2     cmdCopy            COPY
      CommandButton3     cmdPlot            NEW TRACE
      PictureBox1        picGraph 




4. Change the LinkMode Property of Form1 to "1-Source."



5. Paste the following code in Form1:

   
         Option Explicit
   
         Const CF_LINK = &HBF00
         Const CF_TEXT = 1
         Const CF_BITMAP = 2
         Const CF_METAFILE = 3
         Const CF_DIB = 8
         Const CF_PALETTE = 9
   
         Const NONE = 0         ' 0 - None
         Const LINK_SOURCE = 1    ' 1 - Source (forms only)
   
         Dim Trace(0 To 100)  As Integer
         Dim TraceColor As Integer
   
         Private Sub cmdClose_Click()
            Unload Me
         End Sub
   
         Private Sub cmdCopy_Click()
            Form1.LinkMode = NONE
            Form1.LinkTopic = "Main"
            Form1.LinkMode = LINK_SOURCE
            Clipboard.Clear
            Clipboard.SetText "DDEDEMO|Main!picGraph", CF_LINK
            Clipboard.SetData picGraph.Image, CF_BITMAP 'Image
         End Sub
   
         Private Sub cmdPlot_Click()
            GenerateTrace
            PlotTrace
         End Sub
   
         Private Sub Form_Load()
            Form1.LinkMode = NONE
            GenerateTrace
         End Sub
   
         Private Sub Form_Unload(Cancel As Integer)
            End
         End Sub
   
         Private Sub GenerateTrace()
            Dim I As Integer
            For I = 0 To 100
               Trace(I) = Int((100 - 0 + 1) * Rnd + 0)
            Next I
            TraceColor = Int((6 - 1 + 1) * Rnd + 1)
         End Sub
   
         Private Sub PlotTrace()
            Dim I As Integer
            Dim Y As Integer
            Dim LastY As Integer
            picGraph.Cls
            picGraph.AutoRedraw = False
            picGraph.AutoRedraw = True
            picGraph.Scale (-10, 110)-(110, -10)
            picGraph.DrawStyle = 0
            picGraph.Line (0, 0)-(100, 100), , B
            For I = 0 To 100 Step 10
               picGraph.DrawStyle = 0
               picGraph.Line (0, I)-(-2, I)
               picGraph.Line (I, 0)-(I, -2)
               picGraph.DrawStyle = 2
               picGraph.Line (0, I)-(100, I)
               picGraph.Line (I, 0)-(I, 100)
            Next I
            picGraph.DrawStyle = 0
            For I = 1 To 100
               picGraph.Line (I - 1, Trace(I - 1))-(I, Trace(I)), _
               QBColor(TraceColor)
            Next I
            If Form1.LinkMode = 1 Then picGraph.LinkSend
         End Sub 




6. Press the F5 key to run the program.



7. Click COPY.



8. Open an instance of Word.



9. Select Paste Special from the Edit menu. In the Paste Special screen, select Paste Link and Device Independent Bitmap. Note that the bitmap in the Visual Basic program is copied to the Word document.



10. Switch back to the running Visual Basic program. Click NEW TRACE a few times. The bitmap in Word only changes the first time NEW TRACE is selected, and subsequent updates fail to show up.
    
    NOTE: In Visual Basic 4, the same situation fails on the first update with the following error:

    Error 293: DDE Method invoked with no channel open

Additional query words: kbDSupport kbdss kbDDE kbVBp kbVBp500bug kbVBp600bug

Keywords : kbGrpVB
Version : WINDOWS:5.0,6.0,97
Platform : WINDOWS
Issue type : kbbug