Simple Form based authentication example in ASP.Net

In this article I will explain with example how to implement simple Form based authentication using Login page and Login control in ASP.Net using C#.

The Form based authentication has been implemented using ASP.Net Membership Provider.

Database

I am making use of the same database table Users which was used in the article Simple User Registration Form Example in ASP.Net.

This example consists of two pages Login page (Login.aspx) using which the user will login and the Landing page (Home.aspx) which is the page user will be redirected after successful authentication.

 Login Page

This is the login form which will do the following:-

1. Authenticate user by verifying Username and Password.

2. Make sure user has activated his account. Refer my article for details Send user Confirmation email after Registration with Activation Link in ASP.Net

  HTML Markup

The HTML markup consists of an ASP.Net Login control for which the OnAuthenticate event handler has been specified.

<form id="form1" runat="server">

<asp:Login ID = "Login1" runat = "server" OnAuthenticate= "ValidateUser"></asp:Login>

</form>

Namespaces

You will need to import the following namespaces.

C#

using System.Data;

using System.Configuration;

using System.Data.SqlClient;

using System.Web.Security;

Stored Procedure to Validate the User Credentials

The following stored procedure is used to validate the user credentials, this stored procedure first checks whether the username and password are correct else returns -1.

If the username and password are correct but the user has not been activated then the code returned is -2.

If the username and password are correct and the user account has been activated then UserId of the user is returned by the stored procedure.

CREATE PROCEDURE [dbo].[Validate_User]

      @Username NVARCHAR(20),

      @Password NVARCHAR(20)

AS

BEGIN

      SET NOCOUNT ON;

      DECLARE @UserId INT, @LastLoginDate DATETIME

     

      SELECT @UserId = UserId, @LastLoginDate = LastLoginDate

      FROM Users WHERE Username = @Username AND [Password] = @Password

     

      IF @UserId IS NOT NULL

      BEGIN

            IF NOT EXISTS(SELECT UserId FROM UserActivation WHERE UserId = @UserId)

            BEGIN

                  UPDATE Users

                  SET LastLoginDate = GETDATE()

                  WHERE UserId = @UserId

                  SELECT @UserId [UserId] -- User Valid

            END

            ELSE

            BEGIN

                  SELECT -2 -- User not activated.

            END

      END

      ELSE

      BEGIN

            SELECT -1 -- User invalid.

      END

END

Validating the User Credentials

The below event handler gets called when the Log In button is clicked. Here the Username and Password entered by the user is passed to the stored procedure and its status is captured and if the value is not -1 (Username or password incorrect) or -2 (Account not activated) then the user is redirected to the Home page using FormsAuthentication RedirectFromLoginPage method.

C#

protected void ValidateUser(object sender, EventArgs e)

{

    int userId = 0;

    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;

    using (SqlConnection con = new SqlConnection(constr))

    {

        using (SqlCommand cmd = new SqlCommand("Validate_User"))

        {

            cmd.CommandType = CommandType.StoredProcedure;

            cmd.Parameters.AddWithValue("@Username", Login1.UserName);

            cmd.Parameters.AddWithValue("@Password", Login1.Password);

            cmd.Connection = con;

            con.Open();

            userId = Convert.ToInt32(cmd.ExecuteScalar());

            con.Close();

        }

        switch (userId)

        {

            case -1:

                Login1.FailureText = "Username and/or password is incorrect.";

                break;

            case -2:

                Login1.FailureText = "Account has not been activated.";

                break;

            default:

                FormsAuthentication.RedirectFromLoginPage(Login1.UserName, Login1.RememberMeSet);

                break;

        }

    }

}

Home Page

After successful login user will be redirected to this page.

 

HTML Markup

In this page I have made use of ASP.Net LoginName control to display the name of the Logged In user and LoginStatus control to allow user Logout.

<div>

    Welcome

    <asp:LoginName ID="LoginName1" runat="server" Font-Bold = "true" />

    <br />

    <br />

    <asp:LoginStatus ID="LoginStatus1" runat="server" />

</div>

Namespaces

You will need to import the following namespaces.

C#

using System.Web.Security;

Verify whether User has Logged In

Inside the Page Load event, first we verify whether the User is authenticated using the IsAuthenticated property. If the user is not authenticated then he is redirected back to the Login page using FormsAuthentication RedirectToLoginPage method.

C#

protected void Page_Load(object sender, EventArgs e)

{

    if (!this.Page.User.Identity.IsAuthenticated)

    {

        FormsAuthentication.RedirectToLoginPage();

    }

}

Web.Config Configuration

You will need to add the following configuration in the Web.Config file in the <system.web> section.

<authentication mode="Forms">

 <formsdefaultUrl="~/Home.aspx" loginUrl="~/Login.aspx" slidingExpiration="true" timeout="2880"></forms>

</authentication>