Function Cjt_AddtoFile(SourceFile,TargetFile:string):Boolean; var Target,Source:TFileStream; MyFileSize:integer; begin Source:=TFileStream.Create(SourceFile,fmOpenRead or fmShareExclusive); Target:=TFileStream.Create(TargetFile,fmOpenWrite or fmShareExclusive); Target.Seek(0,soFromEnd);//往尾部添加资源 Target.CopyFrom(Source,0); MyFileSize:=Source.Size+Sizeof(MyFileSize);//计算资源大小,并写入辅程尾部 Target.WriteBuffer(MyFileSize,sizeof(MyFileSize)); Target.Free; Source.Free; Result:=True; end; 为什么往尾部添加资源 写进去的一定是Sizeof(MyFileSize);呢?