private void login_Click(object sender, RoutedEventArgs e)
 {
     try {
         SqlConnection sql = new SqlConnection("");
         sql.Open();
         SqlDataAdapter selen = new SqlDataAdapter("SELECT * FROM LOGIN WHERE USERN = '" + user.Text + "' AND PASS = '******'", sql);
         DataTable      dt    = new DataTable();
         selen.Fill(dt);
         //Class1.login();
         if (dt.Rows[0][2].Equals("1"))
         {
             question create = new question();
             create.ShowDialog();
             this.Close();
         }
         else if (dt.Rows[0][2].Equals("0"))
         {
             Test_Take t = new Test_Take();
             t.ShowDialog();
             this.Close();
         }
     } catch
     {
         MessageBox.Show("Does not exist!");
         register r = new register();
         r.ShowDialog();
         this.Hide();
     }
 }
        private void lblRegister_MouseDoubleClick(object sender, MouseButtonEventArgs e)
        {
            register register = new register();

            register.ShowDialog();
            this.Hide();
        }