What's _contentWrapper, why it's null, and how to initialize it?

[أشرف]

Greetings,

Whenever I try to call the client side set_contentElement method of any tooltip object I get a null reference error because _contentWrapper is null. Here's the relevant excerpt from the RadControls code:

set_contentElement:function(contentElement){this._contentWrapper.innerHTML="";
…

It tries to set the innerHTML of _contentWrapper, but it's set to null, so the code breaks.

What's the role of _contentWrapper? And how to initialize it?

[Shinu]

Hi Ashraf,

Please have a look into the sample code snippet I tried and check this online demo and help documentation for further information about ContentElement in RadToolTip.

ASPX:

<asp:ListBox ID="lbSelectedLanguages" runat="server" Width="151px">
    <asp:ListItem Text="Click to select"></asp:ListItem>
</asp:ListBox>
<telerik:RadToolTip runat="server" ID="RadToolTip3" HideEvent="ManualClose" Position="MiddleRight"
    TargetControlID="lbSelectedLanguages">
    <asp:CheckBoxList ID="cblLanguages" runat="server">
        <asp:ListItem Text="English" Value="en"></asp:ListItem>
        <asp:ListItem Text="German" Value="de"></asp:ListItem>
        <asp:ListItem Text="French" Value="fr"></asp:ListItem>
    </asp:CheckBoxList>
    <asp:Button ID="Button1" runat="server" Text="Select" OnClientClick="InsertLanguages(); return false;">
    </asp:Button>
</telerik:RadToolTip>

JavaScript:

<script type="text/javascript">
    function InsertLanguages() {
        var tooltip = $find("<%=RadToolTip3.ClientID %>");
        //get the html element, holding the content of the tooltip
        var contentElement = tooltip.get_contentElement();
        alert(contentElement.innerHTML);
        //set a new html element to tooptip
        contentElement.innerHTML = "<span>demo</span>";
        alert(contentElement.innerHTML);
    }
</script>

Thanks,
Shinu.

[أشرف]

Greetings and thanks for your reply,

The tooltip I have is created in the code not the markup. I created a custom control that displays itself in a tooltip.
I instantiate a tooltip and add a Literal control to its Controls collection.

I'm not on my office now, but when I was there, I tested with a RadTooltip created in the markup, that has a static DIV with some text in the content template, and still the problem occurred.

I think this should be filed as a bug, or otherwise Telerik should give instructions on how to instantiate this object.

[أشرف]

With the setup you created, if I call set_contentElement the same problem occurs because _contentWrapper is null.

After some digging I found that this hack solves the problem:

var tooltip = $find("component id here");

    if(!tooltip.isCreated())
        tooltip._createUI(); // HACK:

    tooltip.set_contentElement(elem);

Again calling a private member, which I don't like. My code has a lot of _ members references.
I think _createUI should be public then.