using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Threading;

namespace ConsoleApplication79
{
class Program
    {
        [DllImport("user32.dll", EntryPoint = "FindWindow", CharSet = CharSet.Auto)]
private extern static IntPtr FindWindow(string classname, string captionName);

        [DllImport("user32.dll", EntryPoint = "FindWindowEx", CharSet = CharSet.Auto)]
private extern static IntPtr FindWindowEx(IntPtr parent,IntPtr child,string classname, string captionName);

        [DllImport("user32.dll")]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, [MarshalAs(UnmanagedType.LPStr)] string lParam);

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
static extern bool SetForegroundWindow(IntPtr hWnd);

static void Main(string[] args)
        {

            IntPtr mwh1 = IntPtr.Zero;

while (mwh1 == IntPtr.Zero)
            {
                Thread.Sleep(1000);
                mwh1 = FindWindow(null, "Windows Security");
            }

            IntPtr panel = FindWindowEx(mwh1, IntPtr.Zero, "DirectUIHWND", null);

            IntPtr CtrlNotifySink = IntPtr.Zero;

            CtrlNotifySink = FindWindowEx(panel, IntPtr.Zero, "CtrlNotifySink", null);

for (int i = 1; i < 7; i++)
            {
                CtrlNotifySink = FindWindowEx(panel, CtrlNotifySink, "CtrlNotifySink", null);
            }

            IntPtr editor = FindWindowEx(CtrlNotifySink, IntPtr.Zero, null, null);

uint WM_SETTEXT = 0xC;

            SendMessage(editor, WM_SETTEXT, IntPtr.Zero, "username");

            CtrlNotifySink = FindWindowEx(panel, CtrlNotifySink, "CtrlNotifySink", null);
            editor = FindWindowEx(CtrlNotifySink, IntPtr.Zero, null, null);

            SendMessage(editor, WM_SETTEXT, IntPtr.Zero, "password");
        }
    }
}