System.Exception: Error HRESULT E_FAIL after migrating from Silverlight 3 to 4

Following is the statement where I am getting the error :

var query = from c in objSearchedData.ToList() sele开发者_运维问答ct c;
q = query;  

Error:

_COMPlusExceptionCode = -532462766 {System.Exception: Error HRESULT E_FAIL has been returned from a call to a COM component.}

I am using DBML and wcf service for the Silverlight 4. I have just migrated from Silverlight 3 the project. In old application its working fine. But after migration I am getting the error above.

Any ideas on how to fix the problem?

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I was getting the same error when calling a method in my domain service from my Silverlight client.

I don't think this applies to you, but I added the HasSideEffect attribute to my method and it fixed it. Maybe this will help someone else.

[Query(HasSideEffects = true)]
public IQueryable<Entity1> GetEntitiesSafe(byte[] bytes)