In this article I will explain with an example, how to implement and use the LoginName control in ASP.Net using C# and VB.Net.
In this article, the login form has been implemented using ASP.Net Login control and Forms Authentication.
The LoginName control is used to display the Username of the Logged in User in ASP.Net.
 
 
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.
Using LoginName control in ASP.Net
 
Note: The SQL for creating the database is provided in the attached sample code.
 
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>
 
Using LoginName control in ASP.Net
 
 
Namespaces
You will need to import the following namespaces.
C#
using System.Data;
using System.Configuration;
using System.Data.SqlClient;
using System.Web.Security;
 
VB.Net
Imports System.Data
Imports System.Configuration
Imports System.Data.SqlClient
Imports 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;
        }
    }
}
 
VB.Net
Protected Sub ValidateUser(sender As Object, e As EventArgs)
    Dim userId As Integer = 0
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As New SqlConnection(constr)
        Using cmd As 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()
        End Using
        Select Case userId
            Case -1
                Login1.FailureText = "Username and/or password is incorrect."
                Exit Select
            Case -2
                Login1.FailureText = "Account has not been activated."
                Exit Select
            Case Else
                FormsAuthentication.RedirectFromLoginPage(Login1.UserName, Login1.RememberMeSet)
                Exit Select
        End Select
    End Using
End Sub
 
 
Home Page
After successful login user will be redirected to this page.
 
Using LoginName control in ASP.Net
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>
 
Using LoginName control in ASP.Net
 
 
Namespaces
You will need to import the following namespace.
C#
using System.Web.Security;
 
VB.Net
Imports 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();
    }
}
 
VB.Net
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    If Not Me.Page.User.Identity.IsAuthenticated Then
        FormsAuthentication.RedirectToLoginPage()
    End If
End Sub
 
 
Web.Config Configuration
You will need to add the following configuration in the Web.Config file in the <system.web> section.
<authentication mode="Forms">
  <forms defaultUrl="~/Home.aspx" loginUrl="~/Login.aspx" slidingExpiration="true" timeout="2880"></forms>
</authentication>
 
 
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