Why do asp.net controls not exist in current contexts in serverside (C#)

Question

Why do asp.net controls not exist in current contexts in serverside (C#)

Donald Symmons 2,246

I have label and textbox controls inside of a Gridview control, but none of them is recognized in the server side window. Why is that please, and how can I make the server side recognize these controls be it textbox or label or other controls?

 <asp:GridView ID="Gridview2" runat="server" Font-Size="10pt" HeaderStyle-Font-Size="10pt" CellPadding="6" GridLines="None" ShowFooter="True" AutoGenerateColumns="False" HeaderStyle-Font-Bold="false"
                        Style="width: 100%" FooterStyle-BackColor="#fdfdfd" HeaderStyle-ForeColor="#000000" Height="50px" HeaderStyle-Height="10px">
                        <Columns>
                            <asp:TemplateField HeaderText="Column1" ItemStyle-Width="40%" HeaderStyle-Font-Bold="false">
                                <ItemTemplate>
                                    <asp:TextBox ID="textBox1" runat="server" Class="form-control" Width="100%" Font-Size="10pt" Style="overflow: hidden; text-transform: capitalize; resize: none;" oninput="Resize(this)" />
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:TemplateField HeaderText="Column2" ItemStyle-Width="10%" HeaderStyle-Font-Bold="false">
                                <ItemTemplate>
                                    <asp:TextBox CssClass="form-control" ID="txtQuantity" Font-Size="10pt" runat="server" Width="100%" />
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:TemplateField HeaderText="Column3" ItemStyle-Width="25%" HeaderStyle-Font-Bold="false">
                                <ItemTemplate>
                                    <asp:Label runat="server" ID="hero-lbl" Style="font-weight: 400;"></asp:Label>
                                    <asp:TextBox ID="TxtBx" runat="server" Font-Size="10pt" Width="90%" placeholder="0.00" />
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:TemplateField HeaderText="Column4" ItemStyle-Width="50%" HeaderStyle-Font-Bold="false">
                                <ItemTemplate>
                                    <asp:Label class="c-info" runat="server" ID="Infolabel" Style="font-weight: 400;"></asp:Label>
                                </ItemTemplate>
                            </asp:TemplateField>
                        </Columns>
                    </asp:GridView>

Answer 1

Lan Huang-MSFT 20,136 Microsoft Vendor

Hi @Donald Symmons,

For nested controls, you need to use the FindControl method to find the corresponding control.

FindControl("ControlId")

foreach (GridViewRow row in Gridview2.Rows)
{
    if (row.RowType == DataControlRowType.DataRow)
    {
        Label lb1 = (Label)row.FindControl("textBox1");
        lb1.Text = "A";
        TextBox tb1 = (TextBox)row.FindControl("Infolabel");
        tb1.Text = "B";
    }
}

Best regards,
Lan Huang

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Donald Symmons 2,246

Hi @Lan Huang-MSFT ,

Sorry I forgot to mention that I want to display dropdown value in the labels that are inside gridview

My DropDown

<asp:DropDownList ID="DropDown1" runat="server" CssClass="form-control" AutoPostBack="true" OnSelectedIndexChanged="SelectedIndexChanged">                                                             </asp:DropDownList>

C#

 protected void SelectedIndexChanged(object sender, EventArgs e)
        {
            DropDown1.SelectedItem.Text = DropDown1.SelectedItem.Text.ToString();
            hero-lbl.Text = DropDown1.SelectedItem.Value.ToString();
            Infolabel.Text = DropDown1.SelectedItem.Value.ToString();
        }

Lan Huang-MSFT 20,136 Microsoft Vendor

Hi @Donald Symmons,

You just assign DropDown1.SelectedItem.Value.ToString() to the control once you find it.

Note that you cannot use hero-lbl, but hero_lbl. Only combinations of alphanumeric characters and the underscore character (_) are valid values for this property.

 protected void SelectedIndexChanged(object sender, EventArgs e)
 {
     DropDown1.SelectedItem.Text = DropDown1.SelectedItem.Text.ToString();

     foreach (GridViewRow row in Gridview2.Rows)
     {
         if (row.RowType == DataControlRowType.DataRow)
         {
             Label lb1 = (Label)row.FindControl("hero_lbl");
             lb1.Text = DropDown1.SelectedItem.Value.ToString();
             Label lb2 = (Label)row.FindControl("Infolabel");
             lb2.Text = DropDown1.SelectedItem.Value.ToString();

         }
     }
 }

Why do asp.net controls not exist in current contexts in serverside (C#)

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