从物化的'System.Byte []'类型到可为空的'System.Byte'类型的指定强制转换无效

    public virtual ObjectResult<Nullable<byte>> GetPersonalPicture3(Nullable<System.Guid> contactId)
    {
        var contactIdParameter = contactId.HasValue ?
            new ObjectParameter("ContactId", contactId) :
            new ObjectParameter("ContactId", typeof(System.Guid));

        return ((IObjectContextAdapter)this).ObjectContext.ExecuteFunction<Nullable<byte>>("GetPersonalPicture3", contactIdParameter);
    }
    public virtual ObjectResult<Nullable<byte>>