Delphi 内存流与字符串之间互相转换

Delphi中的内存流还算比较好用的，有时候需要与字符串互转，网络上找到几个函数保存备用！

//字符串保存到文件中，返回成功与否
function StringToFile(mString: string; mFileName: TFileName): Boolean;
var
  vFileChar: file of Char;
  I: Integer;
begin
{$I-}
  AssignFile(vFileChar, mFileName);
  Rewrite(vFileChar);
  for I := 1 to Length(mString) do
    Write(vFileChar, mString[I]);
  CloseFile(vFileChar);   
{$I+}
  Result := (IOResult = 0) and (mFileName <> '');
end;

//从文件中读出字符串
function FileToString(mFileName: TFileName): string;
var
  vFileChar: file of Char;
  vChar: Char;
begin
  Result := '';   
{$I-}
  AssignFile(vFileChar, mFileName);
  Reset(vFileChar);

  while not Eof(vFileChar) do
  begin
    Read(vFileChar, vChar);
    Result := Result + vChar;
  end;
  CloseFile(vFileChar);   
{$I+}
end;

//把内存流中的字节数组转化为string类型
function StreamToString(mStream: TStream): string;
var
  I: Integer;
begin
  Result := '';
  if not Assigned(mStream) then
    Exit;
  SetLength(Result, mStream.Size);
  for I := 0 to Pred(mStream.Size) do
  try
    mStream.Position := I;
    mStream.Read(Result[Succ(I)], 1);
  except
    Result := '';
  end;
end;

//把字符串存入内存流中，返回成功与否
function StringToStream(mString: string; mStream: TStream): Boolean;
var
  I: Integer;
begin
  Result := True;
  try
    mStream.Size := 0;
    mStream.Position := 0;
    for I := 1 to Length(mString) do
      mStream.Write(mString[I], 1);
  except
    Result := False;
  end;
end;