SendMessage and Handles

a) Call the SendMessage API,
You first declare it like this

[DllImport("user32.dll", CharSet=CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, uint msg, IntPtr wParam,
ref Point lParam);

then call it like any other method.

b) Code a "POINT" structure in C# for use in the call, or
You can use System.Drawing.Point in its place.

c) Find the windows handle of the Rich Text box.

a) Call the SendMessage API,
Check out http://www.pinvoke.net. It will have the declaration of
SendMessage. You might have to tweak it for your specific message. In the
case of SetScrollPos, you will want to use this:

[DllImport("user32.dll", CharSet = CharSet.Auto, EntryPoint = "SendMessage",
ExactSpelling = false)]
static extern int SendEmSetScrollPosMessage(
IntPtr hWnd,
[MarshalAs(UnmanagedType.U4)]
int Msg,
IntPtr wParam,
ref System.Drawing.Point lParam);
b) Code a "POINT" structure in C# for use in the call, or
You can use System.Drawing.Point. It will marshal correctly.
c) Find the windows handle of the Rich Text box.
The RichTextBox control exposes a Handle property which you can use to
get the handle. Actually, the Control class exposes it, so all controls
expose their handle.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

All of which means that I have a very long way to go to achieve a very
simple function. Can anyone please point me at some code that does this
please? Better still, can I achieve this in native C# code?

Thanks
Steve

Steve,

See inline:

a) Call the SendMessage API,

Check out http://www.pinvoke.net. It will have the declaration of
SendMessage. You might have to tweak it for your specific message. In
the case of SetScrollPos, you will want to use this:

[DllImport("user32.dll", CharSet = CharSet.Auto, EntryPoint =
"SendMessage", ExactSpelling = false)]
static extern int SendEmSetScrollPosMessage(
IntPtr hWnd,
[MarshalAs(UnmanagedType.U4)]
int Msg,
IntPtr wParam,
ref System.Drawing.Point lParam);

b) Code a "POINT" structure in C# for use in the call, or

You can use System.Drawing.Point. It will marshal correctly.

c) Find the windows handle of the Rich Text box.

The RichTextBox control exposes a Handle property which you can use to
get the handle. Actually, the Control class exposes it, so all controls
expose their handle.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

All of which means that I have a very long way to go to achieve a very
simple function. Can anyone please point me at some code that does this
please? Better still, can I achieve this in native C# code?

Thanks
Steve