protected void Suppliers_SelectedIndexChanged(object sender, EventArgs e) { if (Suppliers.SelectedValue == "-1") { // The "Show/Edit ALL" option has been selected SupplierDetails.DataSourceID = "AllSuppliersDataSource"; // Reset the page index to show the first record SupplierDetails.PageIndex = 0; } else { // The user picked a particular supplier SupplierDetails.DataSourceID = "SingleSupplierDataSource"; } // Ensure that the DetailsView and GridView are in read-only mode SupplierDetails.ChangeMode(DetailsViewMode.ReadOnly); ProductsBySupplier.EditIndex = -1; // Need to "refresh" the DetailsView SupplierDetails.DataBind(); }