Why I am getting this error ,ControlID could not be found for the trigger in UpdatePanel?

Question

It is very bad situation,sometimes in some pages of my web application i get this error:

A control with ID 'BtnSubmit' could not be found for the trigger in UpdatePanel 'UpdatePanel3'.

but if i build again and load that page it loads corectlly,but after that if i reload the page get error again,

why it is this way?How could i fix it,or find what is the detail of my problem?

in my updatepanel i dont have trigger BtnSubmit and i know the default value of 'ChildrenAsTriggers' properties if updatepanel is true,so please help me

Answer 1

May be you are doing this:

 <asp:UpdatePanel ID="UpdatePanel3" runat="server">
    <Triggers>
       <asp:AsyncPostBackTrigger ControlID="BtnSubmit" /> //since BtnSubmit not declared any where or BtnSubmit is not accessible for UpdatePanel3
    </Triggers>
    <ContentTemplate>
       <%-- Content--%>
    </ContentTemplate>
  </asp:UpdatePanel>

try adding Button(BtnSubmit) where UpdatePanel3 can access. you can add within updatepanel or outside.

<asp:Button ID="BtnSubmit" runat="server" Text="Button" />

Answer 2

tank you @ashwini but i found that my master page .cs file was damaged, i deleted masterpage and created it again, and now every thing is ok. it take my time because i didn't get any thing of the error message! thank to any way.