delphi2010 rtti的遍历记录

Question

type
 myrec = record
 id:dWord;
 name:array[0..31] of  WideChar;
 three:dword;
 count:dword;
 ShuXing:Single;
 ShuXing2:dword;
 ShuXing3:dWORD;

  end;

var
  Form1: TForm1;
  mystr:TMemoryStream;
  nowmyrec:myrec;

implementation
 USES Rtti;
{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);


var
  rttiContext: TRttiContext;
  rttiType: TRttiType;
  fields: TArray<TRttiField>;
  item: myrec;
  i:word;
begin
mystr:=TMemoryStream.Create;
mystr.LoadFromFile(ExtractFilePath(Application.exename)+'1.data');
mystr.Position:=20;
mystr.readbuffer(nowmyRec,88);




 rttiType := rttiContext.GetType(TypeInfo(myRec));
  fields := rttiType.GetFields;
   for i := low(fields) to high(fields) do
   begin
Memo1.Lines.Add(fields[i].GetValue(@nowmyRec).ToString );


   end;

end;

end.

myrec.name是汉字，myrec.name的长度是64字节，我无法读取myrec.name进行备忘录，请帮助我!!!

Answer 1

我使用的是 Delphi 2010，我发现您的代码存在一些问题。首先，我无法让 RTTI 方法与字符数组的内联声明一起使用。我将其更改为:

type
  TCharArray = array[0..31] of WideChar;
  TRec = record
    id:dWord;
    name:TCharArray;
  end;

如果您以内联方式声明数组，则对 GetValue 的调用将引发 AV。这可能在 XE 中已修复，或者很可能是我错误地使用了 RTTI。

其次，您需要对数组进行特殊处理，而不是标量值:

procedure Main;
var
  i, j: Integer;
  rec: TRec;
  rttiContext: TRttiContext;
  rttiType: TRttiType;
  fields: TArray<TRttiField>;
  val: TValue;
  s: string;
begin
  rec.id := 1;
  rec.name := 'Hello Stack Overflow';

  rttiType := rttiContext.GetType(TypeInfo(TRec));
  fields := rttiType.GetFields;
  for i := low(fields) to high(fields) do begin
    val := fields[i].GetValue(@rec);
    if val.IsArray then begin
      s := '';
      for j := 0 to val.GetArrayLength-1 do begin
        s := s+val.GetArrayElement(j).ToString;
      end;
      Writeln(s);
    end else begin
      Writeln(val.ToString);
    end;
  end;
end;

输出:

1
Hello Stack Overflow

这显然不是生产代码，但它至少应该让您重新上路!

附注这是我第一次了解新的 RTTI 功能。看起来很漂亮!