WowSlashCommand.cs

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WoWChat
{
    class WoWSlashCommand
    {

        [DllImport("user32.dll")]
        private static extern int SendMessage(IntPtr thWnd, int msg, int wParam, IntPtr lParam);

        private const int VK_CONTROL = 0xA2;
        private const int WM_KEYDOWN = 0x100;
        private const int WM_KEYUP = 0x101;
        private const int VK_RETURN = 0x0D;

        public static void send(IntPtr hWnd, string slashCommand)
        {
            Object savedClipboard = Clipboard.GetDataObject();
            Clipboard.SetText(slashCommand);

            SendMessage(hWnd, WM_KEYDOWN, VK_RETURN, IntPtr.Zero);
            SendMessage(hWnd, WM_KEYUP, VK_RETURN, IntPtr.Zero);

            SendMessage(hWnd, WM_KEYDOWN, VK_CONTROL, IntPtr.Zero);
            SendMessage(hWnd, WM_KEYDOWN, 0x56, IntPtr.Zero);
            SendMessage(hWnd, WM_KEYUP, 0x56, IntPtr.Zero);
            SendMessage(hWnd, WM_KEYUP, VK_CONTROL, IntPtr.Zero);

            SendMessage(hWnd, WM_KEYDOWN, VK_RETURN, IntPtr.Zero);
            SendMessage(hWnd, WM_KEYUP, VK_RETURN, IntPtr.Zero);

            Clipboard.SetDataObject(savedClipboard);
        }
    }
}