delphi - 如何访问子类中另一个属性隐藏的属性？

Question

我正在写一个TCustomDBGrid需要访问 protected 属性 Options( TGridOptions ) 的后代组件，该属性是 TCustomGrid 的父类 ( TCustomDBGrid ) 的一部分目的。问题是在 TCustomDBGrid 类中存在一个同名的属性重新引入，但具有另一种类型 ( TDBGridOptions )。

检查简化了此声明

 TCustomGrid=  = class(TCustomControl)
 protected
  //I need to access this property
  property Options: TGridOptions read FOptions write SetOptions
      default [goFixedVertLine, goFixedHorzLine, goVertLine, goHorzLine,
      goRangeSelect];
 end;

  TCustomDBGrid = class(TCustomGrid)
  protected
    //a property with the same name is reintroduced in this class
    property Options: TDBGridOptions read FOptions write SetOptions
      default [dgEditing, dgTitles, dgIndicator, dgColumnResize, dgColLines,
      dgRowLines, dgTabs, dgConfirmDelete, dgCancelOnExit, dgTitleClick, dgTitleHotTrack];   
  end;


  TDBGridEx = class(TCustomDBGrid)
  protected
    //inside of this method I need to access the property TCustomGrid.Options
    procedure FastDraw(ACol, ARow: Longint; ARect: TRect; AState: TGridDrawState);
  end;

我弄清楚了如何使用破解器类访问此属性。

type
  TCustomGridClass=class(TCustomGrid);

{ TDBGridEx }
procedure TDBGridEx.FastDraw(ACol, ARow: Integer; ARect: TRect; AState: TGridDrawState);
var
 LOptions: TGridOptions;
 LRect : TRect;
begin
  ......
  LOptions := TCustomGridClass(Self).Options; //works fine
  LRect := ARect;
  if not (goFixedVertLine in LOptions) then
    Inc(LRect.Right);
  if not (goFixedHorzLine in LOptions) then
    Inc(LRect.Bottom);
  .....
end;

但是只是出于好奇我想知道是否存在另一种解决方法或更好的方法来解决这个问题。

Answer 1

这是使用类助手的另一种解决方法。它不像你的那么好，但很有效。

type
  TCustomGridHelper = class helper for TCustomGrid
    function GetGridOptions: TGridOptions;
  end;

function TCustomGridHelper.GetGridOptions: TGridOptions;
begin
  Result := Self.Options;
end;

procedure TDBGridEx.FastDraw(ACol, ARow: Integer; ARect: TRect;
  AState: TGridDrawState);
var
 LOptions: TGridOptions;
 LRect : TRect;
begin
  ...
  LOptions := Self.GetGridOptions; //works fine
  ...
end;