need help to create a login form in c# using MySql Database

using MySql.Data.MySqlClient;

       String connString = "server = localhost; database = sample;uid = abc;password = 123"; //open the database

MySqlConnection MySqlConn = new MySqlConnection();

MySqlConn.ConnectionString = connString ;

MySqlConn.open();

string msqlStr ="select username ,password from sample";           //Execute the query and fill the result to DataSet 

MySqlCommand command = new MySqlCommand(msqlstr ,MySqlConn);

command.ExecuteQuery();

DataSet ds = new DataSet();

MySQLDataAdapter MyAdapter = new MySQLDataAdapter(msqlStr, MySqlConn);

MyAdapter.fill(ds);

protected Boolean UserValidate()

{

   if(aa)

   {

       return;              //failed login

   }

   if(bb)

   {

      //redirect to the welcome page or others

       return true;        //login successful

    }

}

MySqlConn.close(); //close connection