C# skicka en slumpad sträng till notepad

private void button2_Click(object sender, EventArgs e)
{

Random random = new Random();
int randomNumber = random.Next(1,50);

Cursor.Position = new Point(800, 680); // Rör Pekaren till notepad
System.Threading.Thread.Sleep(100); // väntar 100 ms
mouse_event(MOUSEEVENTF_LEFTDOWN, 0, 0, 0, 0); // Gör ett mouseclick i notepad-
mouse_event(MOUSEEVENTF_LEFTUP, 0, 0, 0, 0); // för att få fokus
System.Threading.Thread.Sleep(200); // väntar igen
SendKeys.Send(CreateRandomPassword(7) + "-" + randomNumber); // skickar strängen
} 

        public static string CreateRandomPassword(int PasswordLength)
        {
            string allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGH JKLMNOPQRSTUVWXYZ0123456789";
            Random rNum = new Random();
            string NewPassWord = "";
            for (int i = 0; i < PasswordLength; i++)
            {
                NewPassWord += allowedChars[rNum.Next(allowedChars.Length)];
            }
            return NewPassWord;
        }

public partial class Form1 : Form
{
    [System.Runtime.InteropServices.DllImport("user32.dll", EntryPoint = "FindWindowEx")]
    public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
    [System.Runtime.InteropServices.DllImport("user32.dll")]
    private static extern int SendMessage(IntPtr hwnd, int msg, int wParam, StringBuilder sb);
    Random r = new Random();

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        System.Diagnostics.Process[] p = System.Diagnostics.Process.GetProcessesByName("notepad");
        if (p.Length > 0 && p[0] != null)
        {
            IntPtr child = FindWindowEx(p[0].MainWindowHandle, new IntPtr(0), "Edit", null);

            int u = SendMessage(child, 0xE, 0, null);
            StringBuilder sb = new StringBuilder(u+1);
            SendMessage(child, 0xD, sb.Capacity, sb);
            sb.Append("\r\nArtist - Spårnummer - " + (r.Next() % 50 + 1).ToString());

            SendMessage(child, 0xC, sb.Length, sb);
        }
    }
}