无法将类型为“ System.Web.UI.WebControls.ContentPlaceHolder”的对象转换为类型为“ System.Web.UI.WebControls.GridViewRow”的对象

Question

I am getting the error on OnSelectedIndexChanging

My aspx file

<asp:GridView CssClass="table table-striped table-hover" ID="product_all_detail_list" runat="server" OnSelectedIndexChanging="product_detail_list_SelectedIndexChanging" OnSelectedIndexChanged="product_all_detail_list_SelectedIndexChanged" >
       <Columns>
            <asp:CommandField ShowSelectButton="True" />
            <asp:TemplateField HeaderText="ID" Visible="false">
                 <ItemTemplate>
                      <asp:Label ID="lb_id" runat="server" Text='<%#Eval("Id") %>'></asp:Label>
                 </ItemTemplate>
            </asp:TemplateField>                           
       </Columns>
</asp:GridView>

The code behind

 protected void product_detail_list_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)
{
    Button btn = sender as Button;
 //   GridViewRow row = btn.NamingContainer as GridViewRow;

    GridViewRow row = (GridViewRow)(((Control)sender).NamingContainer);

    all_details.Visible = true;
    Label id = (Label)row.FindControl("lb_id");
    dal.Fillgrid(product_all_detail_list, q);
}

Is the code is correct? I also tried for GridViewRow row = btn.NamingContainer as GridViewRow;

but getting an error like Object reference not set to an instance of an object.

Answer 1

your btn is not inside the GridView when you call btn.NamingContainer it will give ContentPlaceHolder object.

you will get an exception when you cast ContentPlaceHolder to GridViewRow

try with SelectedIndex like below to get the selected row.

GridViewRow row = product_all_detail_list.Rows[product_all_detail_list.SelectedIndex];

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