To do with SendMessage and Clipboard commands, including Undo

[Sastraxi]

Function UNDO(hWnd As Long)
    SendMessage hWnd, EM_UNDO, 0, 0
End Function

Function ToClip(hWnd As Long)
    SendMessage hWnd, WM_COPY, 0, 0
End Function

Function FromClip(hWnd As Long)
    SendMessage hWnd, WM_PASTE, 0, 0
End Function

Function CleanToClip(hWnd As Long)
    SendMessage hWnd, WM_CUT, 0, 0
End Function

Okay... I have some problems with these.

When I call...

Undo - Just selects all the text.
ToClip - Works, but see FromClip (copy command)
FromClip - Pastes it TWICE. Error might be in ToClip when using that, or CleanToClip while using that(paste command)
CleanToClip - Works, but has same side-effects as ToClip when pasting back (see From Clip) (cut command)

This all works for me.

Private Declare Function SendMessage _
Lib "user32" Alias "SendMessageA" (ByVal hWnd As _
Long, ByVal wMsg As Long, ByVal wParam As Long, _
lParam As Any) As Long

Private Const WM_COPY = &H301
Private Const WM_CUT = &H300
Private Const WM_PASTE = &H302
Private Const WM_UNDO = &H304

Private Function Undo(hWnd As Long)
    SendMessage hWnd, WM_UNDO, 0, 0
End Function

Private Function ToClip(hWnd As Long)
    SendMessage hWnd, WM_COPY, 0, 0
End Function

Private Function FromClip(hWnd As Long)
    SendMessage hWnd, WM_PASTE, 0, 0
End Function

Private Function CleanToClip(hWnd As Long)
    SendMessage hWnd, WM_CUT, 0, 0
End Function

Private Sub Command1_Click()
    ToClip Text1.hWnd
End Sub

Private Sub Command2_Click()
    CleanToClip Text1.hWnd
End Sub

Private Sub Command3_Click()
    Undo Text1.hWnd
End Sub

Private Sub Command4_Click()
    FromClip Text1.hWnd
End Sub

[Sastraxi]

Well... I'm using a RICHtextbox. Is it done differently for a rtb?

Should work.

Private Sub Command1_Click()
    ToClip RichTextBox1.hWnd
End Sub

Private Sub Command2_Click()
    CleanToClip RichTextBox1.hWnd
End Sub

Private Sub Command3_Click()
    Undo RichTextBox1.hWnd
End Sub

Private Sub Command4_Click()
    FromClip RichTextBox1.hWnd
End Sub

Do you have any other code associated with copy/pasting that may influence this code?

[Lord Orwell]

use EM_CANUNDO and see if undoing is allowed. If you are accessing someone else's window, they might not allow it.

Here is the constant for it.

Private Const EM_CANUNDO = &HC6