How To Update TextBox using Update panel in asp.net

Question

I Have a TextBox outside the UpdatePanel and a Button inside the Updatepanel When i click on the Button it show value in TextBox.

I Have Write Following Code.

<%@ Register TagPrefix="AjaxToolKit" Assembly="AjaxControlToolkit"         
    Namespace="AjaxControlToolkit" %>


<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
    <asp:ScriptManager ID="ScriptManager1" runat="server" 
         EnablePageMethods="true" />
    <asp:TextBox ID="TextBox5" runat="server" />
    <asp:UpdatePanel runat="server" ID="Up1">
       <ContentTemplate>
           <asp:Button ID="btn" runat="server" onclick="btn_Click" />
       </ContentTemplate>
    </asp:UpdatePanel>
</asp:Content>

----------Code Behind---------

protected void btn_Click(object sender, EventArgs e)
{
    TextBox5.Text = "20000";
}

Answer 1

Your textbox value can't be updated untill you put it in an update panel.

<ContentTemplate>
  <asp:TextBox ID="TextBox5" runat="server" />
  <asp:Button ID="btn" runat="server" onclick="btn_Click" />
</ContentTemplate>

OR, it would be better if you register a trigger of the button and pull your button out from your update, like...

<asp:UpdatePanel runat="server" ID="upnl" UpdateMode="Conditional" >
<ContentTemplate>
    <asp:TextBox ID="TextBox5" runat="server" />
</ContentTemplate>
<Triggers>
    <asp:AsyncPostBackTrigger ControlID="btn" EventName="Click" />
</Triggers>
</asp:UpdatePanel>