how to update child panel content on event of parent updatepanel content event?

i have a tree in parent UpdatePanel on selection of Parent panel tree i am enablling/disabling the child UpdatePanel button. but it does'nt why? how to update child panel content on event of parent updatepanel content event?

<asp:UpdatePanel runat="server" ID="parentPanel" UpdateMode="conditional">
    <ContentTemplate>
      <asp:TreeView id="tree1" runat="server"></asp:TreeView>
        <div id="div_RemitEditor" style="width:225px; display: none;">
            <asp:UpdatePanel ID="childUpdatePanel" runat="server" UpdateMode="Conditional">
                <ContentTemplate>
                    <asp:Button id="btn1" runat="server"></asp:Button>
                    <Content>
                </ContentTemplate>
            </asp:UpdatePanel>
        </div>
       <asp:TreeView id="tree2" runat="server"></asp:TreeView>
    </ContentTemplate>
</asp:Upda开发者_开发问答tePanel>

You need to set ChildrenAsTriggers="true" on parent UpdatePanel when you specify UpdateMode="Conditional"

In your case, ChildUpdatePanel will automatically update if a Postback Event is triggered in ParentUpdatePanel.

The only reason that enable/disable btn1 not working is that the control you are using doesn't trigger a Postback Event. Therefore, you might want change enable/disable on client side.

Here is my solution.

Let me know if it works.

<asp:ScriptManager ID="MainScriptManager" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel id="parentPanel" runat="server" UpdateMode="Conditional" >
    <ContentTemplate>
        <asp:TreeView ID="tree1" runat="server" ShowCheckBoxes="All">
            <Nodes>
                <asp:TreeNode Checked="true" Expanded="true" Text="Toggle Child Button" >
                    <asp:TreeNode Text="Child" ShowCheckBox="true">
                    </asp:TreeNode>
                </asp:TreeNode> 
            </Nodes>
        </asp:TreeView>
        <div id="div_RemitEditor">
            <asp:UpdatePanel ID="childUpdatePanel" runat = "server">
                <ContentTemplate>
                    <asp:Button ID="btnChild" runat="server" Text = "Child Button"/>
                </ContentTemplate>
            </asp:UpdatePanel>
        </div>
    </ContentTemplate>
</asp:UpdatePanel>