A failure occurs during an explicit reference conversion 显式引用转换期间发生失败。
That indicates that an explicit reference conversion failed ,该异常指示显式引用转换失败。
Exception is thrown when a failure occurs during an explicit reference conversion 当在显式引用转换期间发生失败时,会引发
For an explicit reference conversion to be successful , the source value must be null 为了使显式引用转换成功,源值必须为null (在visual basic中为
For an explicit reference conversion to be successful , the source value must be a null reference nothing in visual basic , or the object type referenced by the source argument must be convertible to the destination type by an implicit reference conversion 为使显式引用转换成功进行,源值必须为空引用(在visual basic中为nothing ) ,或者源参数引用的对象类型必须可以通过隐式引用转换来转换为目标类型。