Message in Chinese (Simplified) (中文(简体))
到值类型“<var>Type Name</var>”的强制转换失败，因为具体化值为 null。结果类型的泛型参数或查询必须使用可以为 null 的类型。
Unlocalized message
The cast to value type '<var>Type Name</var>' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type.
Search by Google