RadHtmlPlaceholder v/s Microsoft webrowser control and windowless mode in SL5

[Zatzh]

We are working on SL5 and the corresponding trial version of telerik update you have provided as of Q1 2012 SP1 as a step towards SL4-SL5 transition .We are using both silverlight webbrowser and radhtmlplaceholder in different scenarios in the same project and our intention is to make webbbowser work in in-browser mode which works with elevated permissions enabled + xap certificate signing + relevant registry keys update and lastly but not least setting the windowless param in corresponding page to false. But radhtmlplaceholder throws an error in in-browser mode saying

"System.InvalidOperationException: RadHtmlPlaceholder requires the "Windowless" parameter of the Silverlight application to be True.
   at Telerik.Windows.Controls.RadHtmlPlaceholder.Init()"

Am i missing something here or is there any such constraints with radhtmlplaceholder control to work only with Windowless = True.

thanks
satheesh s

[Lancelot]

Hi Satheesh s,

The RadHtmlPlaceHolder control currently requires the .apsx or .html page hosting the Silverlight plug-in to have the Windowless parameter to be set to "True".

Below are two examples of how to set this parameter properly:

ASPX

<div style="height: 100%;">

<asp:silverlight id="Xaml1" windowless="true" runat="server" source="~/ClientBin/RadHtmlPlachoderDemo.xap"

minimumversion="2.0.31005.0" width="100%" height="100%" />

</div>


HTML

<div id="silverlightControlHost">
    <object data="data:application/x-silverlight-2," type="application/x-silverlight-2"
        width="100%" height="100%">
        <param name="source" value="ClientBin/RadHtmlPlachoderDemo.xap" />
        <param name="onerror" value="onSilverlightError" />
        <param name="background" value="white" />
        <param name="minRuntimeVersion" value="2.0.31005.0" />
        <param name="autoUpgrade" value="true" />
        <param name="windowless" value="true" />
        <a href="http://go.microsoft.com/fwlink/?LinkID=124807" style="text-decoration: none;">
            <img src="http://go.microsoft.com/fwlink/?LinkId=108181" alt="Get Microsoft Silverlight"
                style="border-style: none" />
        </a>
    </object>
    <iframe style='visibility: hidden; height: 0; width: 0; border: 0px'></iframe>
</div>

Also note that when declaring a RadHtmlPlaceholder control, it is important to note that the control is positioned over the whole Silverlight application. For the moment the only workaround, that they are aware of, is hiding the control (setting its Visibility to Collapsed) while displaying other Silverlight content over it.  

Hope this helps,
Lancelot