If you plan to require Windows 2000 for your application, you can make your standard VB RichTextBox control 100-percent transparent with a few simple API calls. To try this tip, create a new project (or use an existing one), add a RichTextBox control, and add this code and these declarations in a standard module:
Option Explicit' Win32 APIs.Private Declare Function GetWindowLong _ Lib "user32" Alias "GetWindowLongA" _ (ByVal hWnd As Long, _ ByVal nIndex As Long) As LongPrivate Declare Function SetWindowLong _ Lib "user32" Alias "SetWindowLongA" _ (ByVal hWnd As Long, ByVal nIndex As Long, _ ByVal dwNewLong As Long) As LongPrivate Declare Function SetWindowPos Lib "user32" _ (ByVal hWnd As Long, ByVal hWndInsertAfter As _ Long, ByVal X As Long, ByVal Y As Long, _ ByVal cx As Long, ByVal cy As Long, _ ByVal wFlags As Long) As Long ' Style bits.Private Const GWL_EXSTYLE As Long = (-20)Private Const WS_EX_TRANSPARENT As Long = &H20' Force total redraw that shows new styles.Private Const SWP_FRAMECHANGED = &H20Private Const SWP_NOMOVE = &H2Private Const SWP_NOZORDER = &H4Private Const SWP_NOSIZE = &H1Public Function Transparent(ByVal hWnd As Long, _ Optional ByVal Value As Boolean = True) As _ Boolean Dim nStyle As Long Const swpFlags As Long = _ SWP_FRAMECHANGED Or SWP_NOMOVE Or _ SWP_NOZORDER Or SWP_NOSIZE ' Get current style bits. nStyle = GetWindowLong(hWnd, GWL_EXSTYLE) ' Set new bits as desired. If Value Then nStyle = nStyle Or WS_EX_TRANSPARENT Else nStyle = nStyle And Not WS_EX_TRANSPARENT End If Call SetWindowLong(hWnd, GWL_EXSTYLE, nStyle) ' Force redraw using new bits. SetWindowPos hWnd, 0, 0, 0, 0, 0, swpFlags ' Make sure new style took. Transparent = _ (GetWindowLong(hWnd, GWL_EXSTYLE) = nStyle)End FunctionYou can use this function to toggle the transparency of your RichTextBox controls at will:Private Sub Check1_Click() Call Transparent(RichTextBox1.hWnd, _ (Check1.Value = vbChecked))End SubTo be on the safe side, check the OS version before making these calls, as the effects can be rather unpleasant in the wrong environment.
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