Telerik.Web.UI.XXX with ID='' was unable to find an embedded skin with the name 'WebBlue'.

[Alex R.]

General info:
- Sharepoint 2010 + webparts with Telerik controls on it
- Telerik ASP.NET AJAX version 2013.2.717.35
- Both Telerik.Web.UI and Telerik.Web.UI.Skins are in GAC ("C:\Windows\assembly")

After deploying webpart to Sharepoint farm webpart works as expected.But when left web page for a some period of time (more than 1 hour) and after that refresh the page telerik error occurs:

==============================================================================================================
Telerik.Web.UI.RadAjaxLoadingPanel with ID='loadingPanel' was unable to find an embedded skin with the name 'WebBlue'. Please, make sure that the skin name is spelled correctly and that you have added a reference to the Telerik.Web.UI.Skins.dll assembly in your project. If you want to use a custom skin, set EnableEmbeddedSkins=false.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 
Exception Details: System.InvalidOperationException: Telerik.Web.UI.RadAjaxLoadingPanel with ID='loadingPanel' was unable to find an embedded skin with the name 'WebBlue'. Please, make sure that the skin name is spelled correctly and that you have added a reference to the Telerik.Web.UI.Skins.dll assembly in your project. If you want to use a custom skin, set EnableEmbeddedSkins=false.

Source Error: 
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

==============================================================================================================

Telerik registration in  *.vbproj file:
<Reference Include="Telerik.Web.UI, Version=2013.2.717.35, Culture=neutral, PublicKeyToken=121fae78165ba3d4, processorArchitecture=MSIL" />
<Reference Include="Telerik.Web.UI.Skins, Version=2013.2.717.35, Culture=neutral, PublicKeyToken=121fae78165ba3d4, processorArchitecture=MSIL" />

Telerik registration in *.ascx 
<%@ Register assembly="Telerik.Web.UI, Version=2013.2.717.35, Culture=neutral, PublicKeyToken=121fae78165ba3d4" namespace="Telerik.Web.UI" tagprefix="telerik" %>

I read a lot of articles which advice to put assemblies into the GAC, but assemblies are already in the GAC. 

Can you please explain why web part stops working after some period of time and how can I fix this problem?
I assume that this behavior is caused by the ending of user session timeout, but don't know how this influences on skin loading.

Thx,
Alex.

[Alex R.]

Hello support,

Do you have any update for this topic? My client asks me when this error will be fixed.
BTW: the problem is directly related with loading WebBlue skin + timeout because it is not reproduced on Default skin.
Look forward to hearing you.

regards,
Alex.

[Andrey]

Hello,

Default skin is a special case because it is loaded inside the Telerik.Web.UI assembly. All other skins are loaded inside the Telerik.Web.UI.Skins assembly. Could you try to set "Vista" or "Black" and check whether the issue still replicates?

Depending on the type of Project you are working on there are some steps you could follow:

• If you are using project type WebSite simple replace of the DLLs in the Bin folder should do the trick, however if you have referenced the DLLs globally in Web.config file you should make correction to the linked version too.
• If the project is of type WebApplication, you should reference the DLL files and additionally to replace the DLL file in the Lib and Bin folders of your project.

Beside these specific to the type of project steps, there are two common steps that should be done in order to verify that all references are replaced. First close all opened instances of Visual Studio and then clear the content of these folders:

• C:\Users\current_user\AppData\Local\Microsoft\VisualStudio\10.0\ProjectAssemblies
• C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files

Additionally you could check what is the version of the Telerik assembly which is referenced in the GAC if you have installed it in the GAC. You could check this help topic for more information.

Additionally, please note that forum threads does not have guaranteed response time. If you need answers with guaranteed response time you should open support tickets.

Regards,
Andrey
Telerik

[Justin]

I too am having this issue. We are using the Q1 2015 telerik release. I have verified that the Telerik.Web.UI.Skins.dll is added to the assembly. The reference was added to the project and I can see the .dll in the bin folder. I am spelling the name correctly and have in fact tried several different skin names to no avail. I have tried setting the value in the web.config I get the same error. Moreover when I select the Telerik menu option in my visual studio 2010 window, I only see the telerik.web.ui default skins pack.

I also attempted to adjust the view via the designer, but the drop down selection does not even appear in the property list window for the control in Visual Studio 2010. 

I would assume I should just be able to add the .dll and reference to my assembly and be done with it, this seems like a significant bug to anyone who wishes to use this feature.

Any help would be appreciated.

Here is the code:

The aspx page

<%@ Register Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" TagPrefix="telerik" %>

<telerik:RadGrid ID="RadGrid1" Skin="Vista"  OnPreRender="RadGrid1_PreRender"  ViewStateMode="Enabled" OnNeedDataSource="RadGrid1_NeedDataSource" GridLines="Both" runat="server" AutoGenerateColumns="false" AllowPaging="true" AllowSorting="true">
                     <ClientSettings>
                        <Selecting AllowRowSelect="true" />
                        <ClientEvents OnRowSelected="RadGrid1_RowSelected" OnRowDeselected="RadGrid1_RowDeselected" OnRowCreated="RadGrid1_RowCreated" OnGridCreated="RadGrid1_GridCreated"  />
                     </ClientSettings>
                        <MasterTableView DataKeyNames="ID" ClientDataKeyNames="ID" GroupLoadMode="Client" >
                          <GroupByExpressions >
                            <telerik:GridGroupByExpression >
                                <SelectFields>
                                    <telerik:GridGroupByField  FieldAlias="ID" FieldName="ID" HeaderText="Proposal No" FormatString="{0:D}">
                                    </telerik:GridGroupByField>
                                </SelectFields>
                                <GroupByFields>
                                    <telerik:GridGroupByField FieldName="ID" SortOrder="Ascending"></telerik:GridGroupByField>
                                </GroupByFields>
                            </telerik:GridGroupByExpression>
                        </GroupByExpressions>
                        <Columns>
                            <telerik:GridBoundColumn DataField="ID" HeaderText="Proposal No."></telerik:GridBoundColumn>
                            <telerik:GridBoundColumn DataField="Revision" HeaderText="Revision"></telerik:GridBoundColumn>
                            <telerik:GridBoundColumn DataField="partnumber" HeaderText="Part No."></telerik:GridBoundColumn>
                            <telerik:GridBoundColumn DataField="quickship" HeaderText="Quickship No."></telerik:GridBoundColumn>
                            <telerik:GridBoundColumn DataField="datequoted" HeaderText="Date Proposed"></telerik:GridBoundColumn>
                            <telerik:GridBoundColumn DataField="dateexpires" HeaderText="Date Expires"></telerik:GridBoundColumn>
                            <telerik:GridBoundColumn DataField="notes" HeaderText="Notes"></telerik:GridBoundColumn>
                        </Columns>
                     </MasterTableView>
                 </telerik:RadGrid>

[Justin]

I was able to solve the issue by re-running the telerik upgrade wizard via visual studio 2010.

 

[Eric]

Should I have a Telerik menu item in Visual Studio 2013? I don't... If I must, perhaps that is related to my problem as noted here: http://www.telerik.com/forums/how-can-i-continue-to-utilize-legacy-telerik-themes-after-upgrading

[Rumen]

Hello Eric,

Can you install the Telerik VSX Extensions for UI for ASP.NET AJAX from here https://marketplace.visualstudio.com/items?itemName=TelerikInc.TelerikASPNETAJAXVSExtensionsa and restart your Visual Studio? 

This should show the Telerik menu on the VS toolbar.

Regards,
Rumen
Telerik by Progress