Login form validation using C#.net Sqlserver

This tutorial will teach you how to do the login from validation using C#.net and Sqlserver.

Import the Namespaces

using System.Data.SqlClient;

Establish the Database Connection

SqlConnection con = new SqlConnection(“server=.;database=StarAirways;user id=sa;password=123;”);

Add Button

SqlCommand cmd = new SqlCommand("select username,password,role from users where username='" + txtUserName.Text + "' and password='" + txtPassword.Text + "'and role='" + CRole.Text + "'", con);

SqlParameter usernameParam;
usernameParam = new SqlParameter("@username", this.txtUserName.Text);
SqlParameter passwordParams;
passwordParams = new SqlParameter("@password", this.txtPassword.Text);
SqlParameter roleParam;
roleParam = new SqlParameter("@role", this.CRole.SelectedIndex);

cmd.Parameters.Add(usernameParam);
cmd.Parameters.Add(passwordParams);
cmd.Parameters.Add(roleParam);

  cmd.Connection.Open();

  SqlDataReader dr = cmd.ExecuteReader();

  if(txtUserName.Text.Length == 0)
     {
          MessageBox.Show("lUser Name Cannot be Left Bank...");
     }
  else if(txtPassword.Text.Length == 0)
     {
           MessageBox.Show("Password Cannot be Left Blank...");
     }
 else if(CRole.Text.Length == 0)
    {
           MessageBox.Show("Please Select a Role...");
    }
else if(dr.HasRows)
    {
           MessageBox.Show("Welcome to Star Airways");
    }

    else
     {
            MessageBox.Show("username and or password are not foun");
            txtUserName.Clear();
            txtPassword.Clear();
            txtUserName.Focus();
       }
   cmd.Connection.Close();