C#

using System;
using System.Collections.Generic;
using System.Text;

namespace SystemAdmin
{

    class Startup
    {
        public void Main()
        {

            bool loggedIn;

            frmLogin frmlogin = new frmLogin();

            loggedIn = (frmlogin.ShowDialog() == DialogResult.OK);

            if (loggedIn)
            {

                Application.Run(new frmmain());

            }
        }
    }
}

String strusername = txtusername.Text; 

            String Password = txtpassword.Text;
        
            int bl ;

            bl = obj.Check_Login(strusername, strPassword);

            if (bl == 1)
            {
                Me.DialogResult = Windows.Forms.DialogResult.OK;
            }
            else
            {
                MessageBox.Show("Invalid Login");
            }

this.textBox1.SelectionStart = this.textBox1.Text.Length;
this.textBox1.SelectAll();