Linkbutton inside update panel doesnot enable from code behind

Question

In a usercontrol I have an update panel which contains a AjaxFileUpload control and a link button to view the file being uploaded by the AjaxFileUpload control. Ascx page is:

<asp:UpdatePanel runat="server" ID="UpdatePanelUpload" UpdateMode="Conditional">
        <ContentTemplate>
            <asp:Panel runat="server" ID="pnlUploadFile">
                <div class="button-action-row">
                    <h2>
                        <asp:Label ID="lblUploadHeader" runat="server" Text="Upload File"></asp:Label>
                    </h2>
                </div>
                <div class="button-action-row">
                    <asp:AjaxFileUpload ID="AjaxFileUpload1" runat="server" ContextKeys="one" OnUploadComplete="UploadComplete" />
                <span class="right">
                        <asp:LinkButton ID="lnkBtnViewUploadDoc" runat="server" Text="View Supplier Contract"
                            OnClick="lnkBtnViewUploadDoc_Click"></asp:LinkButton></span>
                </div>
            </asp:Panel>
        </ContentTemplate>
        <Triggers>
            <asp:PostBackTrigger ControlID="lnkBtnViewUploadDoc" />
        </Triggers>
    </asp:UpdatePanel> 

This usercontrol is loaded in a modal popup.While usercontrol is loaded it checked if file is available in the location, if not the lnkBtnViewUploadDoc is disabled, which works fine. On UploadComplete event, I made lnkBtnViewUploadDoc enabled. But this is not happening. I also tried moving lnkBtnViewUploadDoc to a different panel and updated that updatepanel on UploadComplete event of AjaxFileUpload1. Where am i getting wrong here.

Answer 1

Try including CausesValidation='false' to your LinkButton.

Answer 2

Can you try with AsyncPostBackTrigger

<asp:AsyncPostBackTrigger ControlID="lnkBtnViewUploadDoc" EventName="Event name"></asp:AsyncPostBackTrigger>