我在这里已经阅读了很多关于将字符串写入TMemoryStream并保存到文件并将字符串读回TMemoryStream的讨论
我不知道我在这里做错了什么,但我的SaveData或我的LoadData都是错误的.我可以在调用SaveData之前检查Title的值,它符合我的预期.但是,当我调用LoadData并检查Title的值时,它是垃圾.任何人都可以告诉我,我做错了
procedure SaveData(FileName: TFileName); var MemStr: TMemoryStream; Title: String; begin MemStr:= TMemoryStream.Create; try MemStr.Seek(0,soFromBeginning); WriteStreamStr( MemStr,TItle ); MemStr.SaveToFile(FileName); finally MemStr.Free; end; end; procedure LoadData(FileName: TFileName); var MemStr: TMemoryStream; Title: String; begin MemStr:= TMemoryStream.Create; try MemStr.LoadFromFile(FileName); MemStr.Seek(0,soFromBeginning); Title := ReadStreamStr( MemStr ); finally MemStr.Free; end; end; procedure WriteStreamInt(Stream : TStream; Num : integer); {writes an integer to the stream} begin Stream.WriteBuffer(Num,SizeOf(Integer)); end; procedure WriteStreamStr(Stream : TStream; Str : string); {writes a string to the stream} var StrLen : integer; begin {get length of string} StrLen := Length(Str); {write length of string} WriteStreamInt(Stream,StrLen); if StrLen > 0 then {write characters} Stream.Write(Str[1],StrLen); end; function ReadStreamInt(Stream : TStream) : integer; {returns an integer from stream} begin Stream.ReadBuffer(Result,SizeOf(Integer)); end; function ReadStreamStr(Stream : TStream) : string; {returns a string from the stream} var LenStr : integer; begin Result := ''; {get length of string} LenStr := ReadStreamInt(Stream); {set string to get memory} SetLength(Result,LenStr); {read characters} Stream.Read(Result[1],LenStr); end;
解决方法
当你使用
Stream.Write(Str[1],StrLen);
您正在将第一个StrLen字节写入流中.但是(unicode)字符串数据实际上是StrLen * SizeOf(Char)字节(您必须考虑char类型的大小).以下应该工作:
Stream.Write(Str[1],StrLen * SizeOf(Str[1]));
从流中读取数据时相同.