delphi - 如何发布整数列表？

Question

我想制作一个包含整数列表作为其序列化属性之一的组件。我知道我无法声明 TList<integer>作为已发布属性，因为它不是从 TPersistent 派生的。我读过，如果您重写 DefineProperties，则可以定义“假”已发布属性，但我不太确定它是如何工作的，特别是在创建一个列表而不是单个值的假属性时。

有人能指出我正确的方向吗？

Answer 1

这是一个使用 DefineBinaryProperty 的最小示例(用 D2007 编写，无泛型):

type
  TTestComponent = class(TComponent)
  private
    FList: TList;

    function GetValueCount: Integer;
    function GetValues(Index: Integer): Integer;
    procedure ReadValueList(Stream: TStream);
    procedure SetValues(Index: Integer; Value: Integer);
    procedure WriteValueList(Stream: TStream);
  protected
    procedure DefineProperties(Filer: TFiler); override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;

    function AddValue(Value: Integer): Integer;
    procedure ClearValues;
    procedure DeleteValue(Index: Integer);

    property ValueCount: Integer read GetValueCount;
    property Values[Index: Integer]: Integer read GetValues write SetValues;
  end;

{ TTestComponent }

function TTestComponent.GetValueCount: Integer;
begin
  Result := FList.Count;
end;

function TTestComponent.GetValues(Index: Integer): Integer;
begin
  Result := Integer(FList[Index]);
end;

procedure TTestComponent.ReadValueList(Stream: TStream);
var
  Count, I, Value: Integer;
begin
  ClearValues;
  Stream.Read(Count, SizeOf(Count));
  for I := 0 to Count - 1 do
  begin
    Stream.Read(Value, SizeOf(Value));
    AddValue(Value);
  end;
end;

procedure TTestComponent.SetValues(Index: Integer; Value: Integer);
begin
  FList[Index] := Pointer(Value);
end;

procedure TTestComponent.WriteValueList(Stream: TStream);
var
  Count, I, Value: Integer;
begin
  Count := ValueCount;
  Stream.Write(Count, SizeOf(Count));
  for I := 0 to Count - 1 do
  begin
    Value := Values[I];
    Stream.Write(Value, SizeOf(Value));
  end;
end;

procedure TTestComponent.DefineProperties(Filer: TFiler);
begin
  inherited DefineProperties(Filer);
  Filer.DefineBinaryProperty('ValueList', ReadValueList, WriteValueList, ValueCount > 0);
end;

constructor TTestComponent.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FList := TList.Create;
  // add some values for testing
  AddValue(0);
  AddValue(1);
  AddValue(2);
end;

destructor TTestComponent.Destroy;
begin
  FList.Free;
  inherited Destroy;
end;

function TTestComponent.AddValue(Value: Integer): Integer;
begin
  Result := FList.Add(Pointer(Value));
end;

procedure TTestComponent.ClearValues;
begin
  FList.Clear;
end;

procedure TTestComponent.DeleteValue(Index: Integer);
begin
  FList.Delete(Index);
end;

.dfm 看起来像这样:

  object TestComponent1: TTestComponent
    Left = 96
    Top = 56
    ValueList = {03000000000000000100000002000000}
  end