Question

I would like to use the code here to suspend screen refresh of a rich text box in code I am writing using F#. I don’t know how to use SendMessage (or WM_SETREDRAW or EM_GETEVENTMASK for that matter). How can I declare and use the relevant functions from F#?

The code:

private void StopRepaint()
{
    // Stop redrawing:
    SendMessage(this.Handle, WM_SETREDRAW, 0, IntPtr.Zero);
    // Stop sending of events:
    eventMask = SendMessage(this.Handle, EM_GETEVENTMASK, 0, IntPtr.Zero);
}

Answer 1

Msdn documents how to declare external functions in F#.

Your function would look something like:

open System
open System.Runtime.InteropServices

module InteropWithNative =
    [<DllImport(@"User32")>]
    extern IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam)