PRB: OLEDropMode=0 Doesn't Stop DragDrop of File to Rich TextBox

• Microsoft Visual Basic Professional and Enterprise Editions for Windows, version 5.0

SYMPTOMS

Setting the OLEDragMode property of a Rich TextBox control to 0-rtfOLEDropNone does not disable the ability to drag files from the Windows Explorer and drop them into the Rich Textbox control.

CAUSE

The control should be allowed to accept dropped files independent of the OLEDragMode property. This behavior is allowed because DragAcceptFiles works independently of OLE drag and drop.

RESOLUTION

You can call the DragAcceptFiles API to set the Rich TextBox control so that it does not accept files in a DragDrop operation.

The following is the declaration for the DragAcceptFiles API function:

   Declare Sub DragAcceptFiles Lib "shell32.dll" (ByVal hwnd As Long, _
        ByVal fAccept As Long)

   DragAcceptFiles ByVal RichTextBox1.hwnd, ByVal 0&

STATUS

This behavior is by design.

MORE INFORMATION

The steps provided below are for the Visual Basic 5.0 IDE.

Steps to Reproduce Behavior

1. Create a new Standard EXE project.

2. Click Components on the Project Menu.

3. Check the "Microsoft Rich Textbox Control" in the Controls Tab of the Components dialog box, and click OK.

4. From the Project Menu, select Add Module to add a new module to the project.

5. Place a Rich Textbox control and two Command buttons on Form1.

6. Add the following code to Module1:

         Declare Sub DragAcceptFiles Lib "shell32.dll" (ByVal hwnd As _
            Long, ByVal fAccept As Long)
   
   

7. Add the following code to Form1:

         Private Sub Command1_Click()
           Me.Caption = "DragDrop Enabled"
           RichTextBox1.OLEDragMode = rtfOLEDragAutomatic
           RichTextBox1.OLEDropMode = rtfOLEDropAutomatic
         End Sub
   
         Private Sub Command2_Click()
           Me.Caption = "DragDrop Disabled"
           RichTextBox1.OLEDropMode = rtfOLEDropNone
           RichTextBox1.OLEDragMode = rtfOLEDragManual
           'Uncomment the following line to disable DragDrop of files
           'DragAcceptFiles ByVal RichTextBox1.hwnd, ByVal 0&
         End Sub
   
         Private Sub Form_Load()
           Me.Caption = "DragDrop Enabled"
           Command1.Caption = "Enable DragDrop"
           Command2.Caption = "Disable DragDrop"
           RichTextBox1.OLEDragMode = rtfOLEDragAutomatic
           RichTextBox1.OLEDropMode = rtfOLEDropAutomatic
         End Sub
   
   

8. Press F5 to run the application.

9. Drag a text file from the Windows Explorer and drop it on the Rich Textbox control. Try doing this with DragDrop Enabled and Disabled. You can still drop a file on the Rich Textbox control after you have run the code in Command2_Click. Uncomment the DragAcceptFiles API call and then try to drop the file on the Rich TextBox control after you have clicked the Disable DragDrop button.

Keywords          : PrgCtrlsCus vb5all
Technology        : kbole
Version           : WINDOWS:5.0
Platform          : WINDOWS
Issue type        : kbprb
Solution Type     : kbworkaround