Sending Ctrl+letter to application using PostMesssage or SendMessage

Hi!

I've been trying to send Ctrl+s to notepad, but havent succesfully manage to do this. I've googled it, but havent found anyone who have sent a ctrl+letter command to a process.

Currently, the sending part of my code look like this:

Code:

IntPtr hWnd = FindWindow("Notepad", null); 
IntPtr hWndChild = FindWindowEx(hWnd, IntPtr.Zero, "Edit", null); 
int VK_CONTROL = (int)0x11;
uint wm_keydown = (uint)0x100; 
uint wm_char = (uint)0x102; 
uint wm_keyup = (uint)0x101; 
 
PostMessage(hWndChild, wm_keydown, VK_CONTROL, 0);       //Send Ctrl down 
PostMessage(hWndChild, wm_keydown, VkKeyScan('s'), 0);   //Send 's' down 
PostMessage(hWndChild, wm_keyup, VkKeyScan('s'), 0);     //Send 's' up 
PostMessage(hWndChild, wm_keyup, VK_CONTROL, 0);         //Send Ctrl up

I've also tried different values for the lParam parameter (taken from Spy++) and to use hWnd instead of hWndChild, but it does not work. Does anyone know any way to send Ctrl+s to notepad using PostMessage (or SendMessage)? I would really appreciate if anyone could post some sample code. Thank you!

reoverload the PostMessage function

Code:

        [return: MarshalAs(UnmanagedType.Bool)]
        [DllImport("user32.dll", SetLastError = true)]
        static extern bool PostMessage(HandleRef hWnd, uint Msg, IntPtr wParam, IntPtr 
lParam);

and pass the LPARAM and WPARAM as IntPtr.
use hWnd instead of the later, but i think the name of the window is not
"Notepad" but "Filename - Notepad" and if it's new instance then it's "Untitled - Notepad"