Selected Text and the Clipboard

All TextBoxes and ComboBoxes have a set of properties for selected text. They are:

PropertyDescription
SelStartAn integer that equals the starting position of the selected block of text. If no text is selected, it equals the position of the cursor.
SelLengthAn integer that equals the number of characters selected.
SelTextA string containing the selected characters (or an empty string [e.g., ""] if no characters are selected).

You can control what text is selected by setting the SelStart and SelLength properties. For example: 

     TxtInput.SetFocus ' Sets txtInput to have the focus
     TxtInput.SelStart = 0 ' Starting at the beginning of the text
     TxtInput.SelLength = Len(Text1.Text) ' Select everything

If you assign a new string to SelText, that string replaces the selected text, and the cursor is placed just after the newly inserted text.

Visual Basic has a Clipboard object, which has a SetText function to which you can send data, and a GetText function from which you can receive data (from the clipboard). It also includes a Clear function, which erases all the data in the clipboard. Here's a good example of the code for the Cut, Copy, and Paste menus in all Windows programs (using whatever control happens to be active, referenced with a special variable named Screen.ActiveControl):

Private Sub mnuCut_Click ()
  Clipboard.Clear
  Clipboard.SetText Screen.ActiveControl.SelText
  Screen.ActiveControl.SelText = ""
End Sub

Private Sub mnuCopy_Click ()
  Clipboard.Clear
  Clipboard.SetText Screen.ActiveControl.SelText
End Sub

Private Sub mnuPaste_Click ()
  Screen.ActiveControl.SelText = Clipboard.GetText()
End Sub

Note that you can't copy, for example, a picture to the clipboard this way. However, you can if you use the following code (this time, just using the Copy command as an example):

Private Sub mnuCopy_Click ()
  Clipboard.Clear
  If TypeOf Screen.ActiveControl Is TextBox Then
    Clipboard.SetText Screen.ActiveControl.SelText
  ElseIf TypeOf Screen.ActiveControl Is ComboBox Then
    Clipboard.SetText Screen.ActiveControl.Text
  ElseIf TypeOf Screen.ActiveControl Is PictureBox Then
    Clipboard.SetText Screen.ActiveControl.Picture
  ElseIf TypeOf Screen.ActiveControl Is ListBox Then
    Clipboard.SetText Screen.ActiveControl.Text
  End If ' Note that no action makes sense for any other control
End Sub
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