How to access the TextArea value from a content page

Question

I have a TextArea control in my content page which is inside an UpdatePanel:

Answer 1

Add <triggers> to your UpdatePanel.

<asp:UpdatePanel runat="server" ...>
    <ContentTemplate>
        ...
    </ContentTemplate>
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="btnSave" EventName="Click" />
    </Triggers>
</asp:UpdatePanel>