title: InvalidOperationException Nullable object must have a value
body: <p>i am using asp.net 4.0 and sql server when i am browing in the application only some times i am seeing this error and if click some thing it resolves can some one suggest me how to overcome this </p>
  
  <p>'System.InvalidOperationException: Nullable object must have a value.
     at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource
  resource)</p>