protected void Page_Load(object sender, EventArgs e) {     if (!this.IsPostBack)     {         DataTable dt = new DataTable();         dt.Columns.AddRange(new DataColumn[1] { new DataColumn("Value", typeof(int)) });         dt.Rows.Add(10);         dt.Rows.Add(20);         dt.Rows.Add(30);         dt.Rows.Add(40);         gvData.DataSource = dt;         gvData.DataBind();     } }