In this article I will explain how to authenticate user using its FaceBook account and get its FaceBook Profile details like UserId, Username, Name, Email and Profile picture in ASP.Net using the Free ASPSnippets FaceBook API.
 
Note: You can download the latest ASPSnippets.FaceBookAPI.dll clicking the download link below.
          Download DLL file
 

Create FaceBook Application and get App Id
You will need to create an application and get an API Key and API Secret


HTML Markup
In the below HTML Markup I have placed an ASP.Net Button btnLogin to authenticate the user through FaceBook and get its profile details like FaceBook UserId, Username, Name, Email and Profile picture.
<asp:Button ID="btnLogin" runat="server" Text="Login with FaceBook" OnClick="Login" />
<asp:Panel ID="pnlFaceBookUser" runat="server" Visible="false">
<hr />
<table>
    <tr>
        <td rowspan="5" valign="top">
            <asp:Image ID="ProfileImage" runat="server" Width="50" Height="50" />
        </td>
    </tr>
    <tr>
        <td>ID:<asp:Label ID="lblId" runat="server" Text=""></asp:Label></td>
    </tr>
    <tr>
        <td>UserName:<asp:Label ID="lblUserName" runat="server" Text=""></asp:Label></td>
    </tr>
    <tr>
        <td>Name:<asp:Label ID="lblName" runat="server" Text=""></asp:Label></td>
    </tr>
    <tr>
        <td>Email:<asp:Label ID="lblEmail" runat="server" Text=""></asp:Label></td>
    </tr>
</table>
</asp:Panel>
 
 
 
Namespaces
You will need to import the following Namespaces
C#
using ASPSnippets.FaceBookAPI;
using System.Web.Script.Serialization;
 
VB.Net
Imports ASPSnippets.FaceBookAPI
Imports System.Web.Script.Serialization
 
 
Data Class
You will need to create the following class which will be used to hold the User Profile details returned from FaceBook after authentication.
C#
public class FaceBookUser
{
    public string Id { get; set; }
    public string Name { get; set; }
    public string UserName { get; set; }
    public string PictureUrl { get; set; }
    public string Email { get; set; }
}
 
VB.Net
Public Class FaceBookUser
    Public Property Id() As String
        Get
            Return m_Id
        End Get
        Set(value As String)
            m_Id = value
        End Set
    End Property
    Private m_Id As String
    Public Property Name() As String
        Get
            Return m_Name
        End Get
        Set(value As String)
            m_Name = value
        End Set
    End Property
    Private m_Name As String
    Public Property UserName() As String
        Get
            Return m_UserName
        End Get
        Set(value As String)
            m_UserName = value
        End Set
    End Property
    Private m_UserName As String
    Public Property PictureUrl() As String
        Get
            Return m_PictureUrl
        End Get
        Set(value As String)
            m_PictureUrl = value
        End Set
    End Property
    Private m_PictureUrl As String
    Public Property Email() As String
        Get
            Return m_Email
        End Get
        Set(value As String)
            m_Email = value
        End Set
    End Property
    Private m_Email As String
End Class
 
 
Authenticate user using FaceBook account
On the click of the ASP.Net Button btnLogin  we redirect the User to FaceBook and ask him to authenticate himself as wells as provide permission to access to his FaceBook profile details like FaceBook UserId, Username, Name, Email and Profile picture
C#
protected void Login(object sender, EventArgs e)
{
    FaceBookConnect.Authorize("user_photos,email", Request.Url.AbsoluteUri.Split('?')[0]);
}
 
VB.Net
Protected Sub Login(sender As Object, e As EventArgs)
    FaceBookConnect.Authorize("user_photos,email", Request.Url.AbsoluteUri.Split("?"c)(0))
End Sub
 
 
 
 
Fetch the user’s FaceBook Profile details
The below code checks for access code (access token) in Query string and then based on the access code it fetches the user’s  FaceBook profile details like FaceBook UserId, Username, Name, Email and Profile picture
 
C#
protected void Page_Load(object sender, EventArgs e)
{
    FaceBookConnect.API_Key = "<Your API Key>";
    FaceBookConnect.API_Secret = "<Your API Secret>";
    if (!IsPostBack)
    {
        if (Request.QueryString["error"] == "access_denied")
        {
            ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('User has denied access.')", true);
            return;
        }
 
        string code = Request.QueryString["code"];
        if (!string.IsNullOrEmpty(code))
        {
            string data = FaceBookConnect.Fetch(code, "me?fields=id,name,email");
            FaceBookUser faceBookUser = new JavaScriptSerializer().Deserialize<FaceBookUser>(data);
            faceBookUser.PictureUrl = string.Format("https://graph.facebook.com/{0}/picture", faceBookUser.Id);
            pnlFaceBookUser.Visible = true;
            lblId.Text = faceBookUser.Id;
            lblUserName.Text = faceBookUser.UserName;
            lblName.Text = faceBookUser.Name;
            lblEmail.Text = faceBookUser.Email;
            ProfileImage.ImageUrl = faceBookUser.PictureUrl;
            btnLogin.Enabled = false;
        }
    }
}
 
VB.Net
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    FaceBookConnect.API_Key = "<Your API Key>"
    FaceBookConnect.API_Secret = "<Your API Secret>"
    If Not IsPostBack Then
        If Request.QueryString("error") = "access_denied" Then
            ClientScript.RegisterStartupScript(Me.GetType(), "alert", "alert('User has denied access.')", True)
            Return
        End If
 
        Dim code As String = Request.QueryString("code")
        If Not String.IsNullOrEmpty(code) Then
            Dim data As String = FaceBookConnect.Fetch(code, "me?fields=id,name,email")
            Dim faceBookUser As FaceBookUser = New JavaScriptSerializer().Deserialize(Of FaceBookUser)(data)
            faceBookUser.PictureUrl = String.Format("https://graph.facebook.com/{0}/picture", faceBookUser.Id)
            pnlFaceBookUser.Visible = True
            lblId.Text = faceBookUser.Id
            lblUserName.Text = faceBookUser.UserName
            lblName.Text = faceBookUser.Name
            lblEmail.Text = faceBookUser.Email
            ProfileImage.ImageUrl = faceBookUser.PictureUrl
            btnLogin.Enabled = False
        End If
    End If
End Sub
 
 
 
Demo
 
Downloads