Data is not updating on RowUpdate event in asp.net gridview

Im trying to update the row in the gridview but data is not updating after entering in textbox.
protected void grvAttendance_RowUpdating(object sender, GridViewUpdateEventArgs e) { grvAttendance.EditIndex = -1; GridViewRow row = (GridViewRow)grvAttendance.Rows[e.RowIndex]; dt = (DataTable)Session["EmployeeDetails"]; TextBox txtTrainingDays = (TextBox)row.FindControl("txtTrainingDays"); TextBox txtPersonalDays = (TextBox)row.FindControl("txtPersonalDays"); Label lblEmpID = (Label)row.FindControl("lblEmpID"); saveEmployeeItem(int.Parse(lblEmpID.Text), int.Parse(txtTrainingDays.Text), int.Parse(txtPersonalDays.Text)); grvAttendance.DataSource = dt; grvAttendance.DataBind(); Session["EmployeeDetails"] = dt; ...