Display number of currently logged in Users of a website in ASP.Net

You need to get the updated user detail from last 15 minut. You can also set it to 30 min or greater than that.

HTML

<form id="form1" runat="server">
<div>
    <table border="0" cellpadding="5" cellspacing="0">
        <tr>
            <td>
                Number of login user
            </td>
            <td>
                <asp:Label ID="lblUserCount" runat="server" />
            </td>
        </tr>
    </table>
    <hr />
    Currently login user
    <br />
    <br />
    <asp:GridView runat="server" ID="gvOnlineUsers" HeaderStyle-BackColor="#3AC0F2" HeaderStyle-ForeColor="White"
        Width="200" />
</div>
</form>

Namespaces

using System.Configuration;
using System.Data.SqlClient;
using System.Data;

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string constr = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT UserId, UserName FROM Users WHERE DATEDIFF(mi,LastLoginDate,GETDATE())  <= 15", con))
            {
                using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    da.Fill(ds);
                    this.lblUserCount.Text = ds.Tables[0].Rows.Count.ToString();
                    this.gvOnlineUsers.DataSource = ds;
                    this.gvOnlineUsers.DataBind();
                }
            }
        }
    }
}

SQL

Simple User Login Form example in ASP.Net

Screenshot