封装了三个对TMemoryStream操作的函数，大牛莫笑

//  TMemoryStream 转化为string字符串
function MemoryStreamToString(M: TMemoryStream): AnsiString;
begin
 SetString(Result, PChar(M.Memory), M.Size div SizeOf(Char));
end;
//  TMemoryStream 写入string字符串
procedure MemoryAddStr(M:TMemoryStream;cStr:String);
begin
  if M=nil then
    M:=TMemoryStream.Create;
   M.Write(cStr[1],Length(cStr)*Sizeof(char));
end;
//  TMemoryStream 保存到文件
procedure MemoryStreamSaveToFile(M:TMemoryStream;cFileName:String);
 Var
   FStream:TFileStream;
 begin
   if FileExists(cFileName) then
     begin
       FStream:=TFileStream.Create(cFileName,fmOpenWrite or fmShareDenyWrite);
       FStream.Position:=FStream.Size;
     end else
       FStream:=TFileStream.Create(cFileName,fmCreate or fmShareDenyWrite);
   FStream.Write(M.Memory^,M.Position);
   FStream.Free;
 end;