如何检测tfilestream是否已释放？

问题描述

是否有办法查看是否正在使用tfile流实例？例如，如果我声明了类型为tfilestream的FS的
，则向其写入缓冲区，然后
最终使用tfilestream.free释放流。我可以检查一下
吗？

is there a way to see if an instace of tfile stream is being used?for example if i declare FS of type tfilestream,write buffer to it andfinally free the stream using tfilestream.free can i check somethinglike:

if
tfilestream.NotActive
then
 //code
if tfilestream.beingused then
 //code
if tfilestream.free = true then
    //code

active 和 beingused 方法不存在，我们也无法测试 tfilestream.free = true 只是为了弥补这一点，以了解我要问的问题

active and beingused methods do not exists for real nor can we test tfilestream.free = true just making this up to give idea what i am trying to ask

推荐答案

您无法以预期的方式进行操作。但是您可以使用 FreeAndNil（）

You can't do it in the way you expect. But you and do it with FreeAndNil()

var
  FS : TFileStream;
begin
  FS := TFileStream.Create(...);
  try
   // Do Work with TFileSTream
  finally
   FreeAndNil(FS);
  end;

  // For some reason you need to check FS is freed.

  if not Assigned(FS) then
  begin
   // Stream was freed.
  end;
end;

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