PRB: Cannot Paste PrintScreen Result to OLE Control

ID: Q193593

The information in this article applies to:

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

SYMPTOMS

Pressing the ALT+PRINTSCRN key combination turns the OLE control's PasteOK property to False, and the bitmap in the clipboard cannot be pasted to the OLE control.

CAUSE

There are two kinds of Clipboard formats; one is the traditional format and the other is the OLE format. Microsoft's Visual Basic OLE control is designed to hold the objects that can either be linked or embedded in the control. It requires the clipboard to contain the OLE information to be pasted into it. However, after pressing the ALT+PRINTSCRN key combination, the clipboard format is in the traditional format. For the same reason, simple metafiles in the clipboard cannot be pasted into the OLE control either.

RESOLUTION

To workaround this problem, the clipboard format needs to be transformed from traditional format to OLE format.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce and Work Around Behavior

The following is an example of using a Rich Textbox to transform the clipboard format from traditional format to OLE format and make the paste possible. The basic idea is to paste the bitmap from the clipboard to a Rich Textbox and then copy it back from the Rich Textbox to the clipboard. In the example, the SendKeys function is used to paste to and copy from the clipboard.

Create a Standard EXE project in Visual Basic. Form1 is created by default.

Put an OLE control on Form1 and keep the default name, OLE1. Click Cancel when the "Insert Object" dialog box comes up.

Put a CommandButton on Form1 and keep the default name, Command1.

Add the following code to the code window of Form1:


      Private Sub Command1_Click()
        if OLE1.PasteOk = True then
            OLE1.Paste
        else
            msgbox "Can not paste!"
        End if
      End Sub

Run the application. Pressing the ALT+PRINTSCRN key combination and then click the CommandButton. The message box "Can not paste!" is displayed, demonstrating the problem.

Stop the application.

Select Components from the Project menu and check "Microsoft Rich Textbox Control X.0."

Add a Rich Textbox to Form1 and keep the default name, RichTextBox1. Make sure its Visible property is set to True and its TabStop property is set to False. Make the Rich Textbox as small as possible and hide it under the CommandButton (because you don't want it to show on the screen). If necessary, right-click on the Rich Textbox and click "Send to Back."

Change the Command1_Click event handler to be:


      Private Sub Command1_Click()
        ' use RichTextBox to transform the clipboard info
        RichTextBox1.TextRTF = ""
        RichTextBox1.SetFocus
        SendKeys "^v", True
        SendKeys "^+{HOME}", True
        SendKeys "^c", True
        RichTextBox1.TextRTF = ""

        if OLE1.PasteOk = True then
            OLE1.Paste
        else
            msgbox "Can not paste!"
        End if
      End Sub

Run the application again. Press the ALT+PRINTSCRN key combination and then click on Command1. This time the screen capture is pasted to the OLE control.

Additional query words: kbDSupport kbDSD kbVBp kbVBp500 kbVBp600 kbOLE kbClipboard

Keywords : kbGrpVB
Version : WINDOWS:5.0,6.0
Platform : WINDOWS
Issue type : kbprb