Problem: $find('<%=RadWindow1.ClientID %>') return null

the problem is :

$find('<%=RadWindow1.ClientID %>') always return null.

i spent much time found out where is the problem.

 

if you added follow code to the RadAjaxManager , you will met the problem.

<telerik:AjaxSetting AjaxControlID="btnShowAddOutlayForm">
            <UpdatedControls>
                <telerik:AjaxUpdatedControl ControlID="RadWindow1" LoadingPanelID="RadAjaxLoadingPanel1" />
            </UpdatedControls>
        </telerik:AjaxSetting>

because, after you clicked button "btnShowAddOutlayForm", the ajax request will update whole RadWindow1.

then the problem was happened.

 

to avoid this problem :

1. remove about code from RadAjaxManager.

2. try to place one "UpdatePanel" or "RadAjaxPanel" in to RadWindow1, then you can update contents in the RadWindow on the server side.

<telerik:RadWindow ID="RadWindow1" runat="server" Animation="Fade" Behaviors="Close,Move"
    Modal="True" AutoSize="false" Title="Test Title" VisibleStatusbar="False" Height="430"
    Width="500" Skin="WebBlue" Visible="true">
    <ContentTemplate>
    <asp:UpdatePanel ID="UpdatePanel2" runat="server" ChildrenAsTriggers="False" UpdateMode="Conditional">
    <ContentTemplate>
        <telerik:RadAjaxPanel ID="RadAjaxPanel2" runat="server" LoadingPanelID="RadAjaxLoadingPanel1">
            <div>
                <!--you code here.-->
            </div>
        </telerik:RadAjaxPanel>
            </ContentTemplate>
</asp:UpdatePanel>
    </ContentTemplate>
</telerik:RadWindow>

 

over