支持自绘画的属性编辑器

//根据True或者False来画一个复选框及布耳值的文本标签
procedure DrawBoolCheckBox(Canvas: TCanvas;
const Rect: TRect; const Value: string);
begin
Canvas.FillRect(Rect);
Canvas.TextRect(Rect, Rect.Left Checked.Width 2,
Rect.Top 1, Value);
if Value = BooleanIdents[False] then
Canvas.Draw(Rect.Left 1, Rect.Top 1, UnChecked)
else
Canvas.Draw(Rect.Left 1, Rect.Top 1, Checked);
end;

{ TSetElementPropertyEx }

// 每个列表项旁边显示一个复选框，用户必须双击
//而不是单击才能切换复选框状态
procedure TSetElementPropertyEx.PropDrawValue(
Canvas: TCanvas; const Rect: TRect; Selected: Boolean);
begin
DrawBoolCheckBox(Canvas, Rect, Value);
end;

{ TBoolPropertyEx }

// 为ByteBool, WordBool和LongBool类型显示复选框
procedure TBoolPropertyEx.PropDrawValue(Canvas: TCanvas;
const Rect: TRect; Selected: Boolean);
begin
DrawBoolCheckBox(Canvas, Rect, Value);
end;

//为全部的集合属性注册一个统一的属性编辑器
function SetMapper(Obj: TPersistent; PropInfo: PPropInfo):
TPropertyEditorClass;
begin
if PropInfo.PropType^.Kind = tkSet then
Result := TSetPropertyEx
else
Result := nil;
end;

procedure Register;
begin
RegisterPropertyEditor(TypeInfo(TFont), nil, '''''''',
TVisualFontProperty);
RegisterPropertyEditor(TypeInfo(TGraphic), nil, '''''''',
TVisualGraphicProperty);
RegisterPropertyEditor(TypeInfo(TComponentName),
TComponent, ''''Name'''', TBoldComponentNameProperty);
RegisterPropertyEditor(TypeInfo(Boolean), nil, '''''''',
TBooleanPropertyEx);
RegisterPropertyEditor(TypeInfo(ByteBool), nil, '''''''',
TBoolPropertyEx);
RegisterPropertyEditor(TypeInfo(WordBool), nil, '''''''',
TBoolPropertyEx);
RegisterPropertyEditor(TypeInfo(LongBool), nil, '''''''',
TBoolPropertyEx);

RegisterPropertyMapper(SetMapper);