ASP.NET/C# GridView Rank column

gridview_with_rank.aspx.cs

public partial class Leaders : System.Web.UI.Page {
    private int rank = 0;  // Rank of the current record in GridView
    private int currentPage = 0;  // tracks current page in GridView
 
    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) {
        // Find label control to update
        Label lblRank = (Label)e.Row.FindControl("lblRank");
 
        // On page reload, rank is reset to 0
        if (rank == 0) {
            // Only run this on subsequent pages
            if($currentPage > 0){
                // Set rank to current index of page * the number of records to display on GridView page
                rank = currentPage * GridView1.PageSize;
            }
        }
 
        // Make sure we actually found our label
        if (lblRank != null) {
            // Increment rank by 1
            rank += 1;
 
            // Set rank label to our new rank value
            lblRank.Text = rank.ToString();
        }
    }
 
    protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e) {
        // Set current page = to index of new GridView page
        currentPage = e.NewPageIndex;
    }
}