TRichEdit 是否支持 Unicode？

Question

我正在尝试围绕TRichEdit 编写一个包装类，它可以将RTF 编码和解码到/从纯文本。

这是我目前写的：

type
  TRTF = class
  private
    FRichEdit : TRichEdit;
    procedure SetText(const AText: string);
    function GetText: string;
    class function Convert(const AInput: string; AEncode: Boolean): string; inline; static;
  public
    constructor Create;
    destructor Destroy; override;
    class function Decode(const AInput: string): string; static;
    class function Encode(const AInput: string): string; static;
  end;

constructor TRTF.Create;
begin
  FRichEdit := TRichEdit.CreateParented(HWND_MESSAGE);
end;

destructor TRTF.Destroy;
begin
  FRichEdit.Free;
  inherited;
end;

function TRTF.GetText: string;
var
  Stream: TStringStream;
begin
  if FRichEdit.PlainText then begin
    Stream := TStringStream.Create('', TEncoding.ANSI);
  end else begin
    Stream := TStringStream.Create('', TEncoding.ASCII);
  end;
  try
    FRichEdit.Lines.SaveToStream(Stream, Stream.Encoding);
    Result := Stream.DataString;
  finally
    Stream.Free;
  end;
end;

procedure TRTF.SetText(const AText: string);
var
  Stream: TStringStream;
begin
  if FRichEdit.PlainText then begin
    Stream := TStringStream.Create(AText, TEncoding.ANSI);
  end else begin
    Stream := TStringStream.Create(AText, TEncoding.ASCII);
  end;
  try
    Stream.Seek(0, TSeekOrigin.soBeginning);
    FRichEdit.Lines.LoadFromStream(Stream);
  finally
    Stream.Free;
  end;
end;

class function TRTF.Convert(const AInput: string; AEncode: Boolean): string;
var
  RTF: TRTF;
begin
  RTF := TRTF.Create;
  try
    RTF.FRichEdit.PlainText := AEncode;
    RTF.SetText(AInput);
    RTF.FRichEdit.PlainText := not AEncode;
    Result := RTF.GetText;
  finally
    RTF.Free;
  end;
end;

class function TRTF.Encode(const AInput: string): string;
begin
  Result := Convert(AInput, True);
end;

class function TRTF.Decode(const AInput: string): string;
begin
  Result := Convert(AInput, False);
end;

对于用户默认 ANSI 代码页可以表示的所有内容，这似乎工作得相当好。

但对于其他字符，它会失败（将它们转换为?）。

有没有一种简单的方法可以在我的代码中启用正确的 Unicode 处理？

当TRichEdit 设置为PlainText := True 时，我尝试使用TEncoding.Unicode 和TEncoding.UTF8 作为TStringStream 的编码，但这不起作用。

Answer 1

我认为你过于复杂了。根本不需要使用 PlainText 属性。将其保留为默认设置 True。然后，要读/写 RTF，请使用 LoadFromStream 和 SaveToStream。要读取/写入纯文本，请使用 Lines.Text 属性。

这是我能做到的最简单的：

type
  TRTF = class
  strict private
    class function CreateRichEdit: TRichEdit; static;
  public
    class function Decode(const AInput: string): string; static;
    class function Encode(const AInput: string): string; static;
  end;

class function TRTF.CreateRichEdit: TRichEdit;
begin
  Result := TRichEdit.CreateParented(HWND_MESSAGE);
end;

class function TRTF.Encode(const AInput: string): string;
var
  RichEdit: TRichEdit;
  Stream: TStringStream;
begin
  RichEdit := CreateRichEdit;
  try
    RichEdit.Lines.Text := AInput;
    Stream := TStringStream.Create;
    try
      RichEdit.Lines.SaveToStream(Stream);
      Result := Stream.DataString;
    finally
      Stream.Free;
    end;
  finally
    RichEdit.Free;
  end;
end;

class function TRTF.Decode(const AInput: string): string;
var
  RichEdit: TRichEdit;
  Stream: TStringStream;
begin
  RichEdit := CreateRichEdit;
  try
    Stream := TStringStream.Create(AInput);
    try
      RichEdit.Lines.LoadFromStream(Stream);
      Result := RichEdit.Lines.Text;
    finally
      Stream.Free;
    end;
  finally
    RichEdit.Free;
  end;
end;