试试这个会解决你的问题
[DllImport("user32.dll", EntryPoint = "FindWindowEx")]
public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
[DllImport("User32.dll")]
public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, string lParam);
private void button6_Click(object sender, EventArgs e)
{
Process[] notepads = Process.GetProcessesByName("notepad");
if (notepads.Length == 0)
{
Process.Start(@"notepad.exe");
Thread.Sleep(100);
}
notepads = Process.GetProcessesByName("notepad");
// return;
if (notepads[0] != null)
{
IntPtr child = FindWindowEx(notepads[0].MainWindowHandle, new IntPtr(0), "Edit", null);
SendMessage(child, 0x000C, 0, "Hello");
}
}