Как получить контекст свойства по его целочисленному значению?
01.01.2007
unit PropertyList; interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, Buttons; type TMyStream = class(TFileStream) private FFred: integer; published property Fred: integer read FFred write FFred; end; type TFrmPropertyList = class(TForm) SpeedButton1: TSpeedButton; ListBox1: TListBox; procedure SpeedButton1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var FrmPropertyList: TFrmPropertyList; implementation {$R *.DFM} uses TypInfo; procedure ListProperties(AInstance: TPersistent; AList: TStrings); var i: integer; pInfo: PTypeInfo; pType: PTypeData; propList: PPropList; propCnt: integer; tmpStr: string; begin pInfo := AInstance.ClassInfo; if (pInfo = nil) or (pInfo^.Kind <> tkClass) then raise Exception.Create('Invalid type information'); pType := GetTypeData(pInfo); {Pointer to TTypeData} AList.Add('Class name: ' + pInfo^.Name); {If any properties, add them to the list} propCnt := pType^.PropCount; if propCnt > 0 then begin AList.Add (EmptyStr); tmpStr := IntToStr(propCnt) + ' Propert'; if propCnt > 1 then tmpStr := tmpStr + 'ies' else tmpStr := tmpStr + 'y'; AList.Add(tmpStr); FillChar(tmpStr[1], Length(tmpStr), '-'); AList.Add(tmpStr); {Get memory for the property list} GetMem(propList, sizeOf(PPropInfo) * propCnt); try {Fill in the property list} GetPropInfos(pInfo, propList); {Fill in info for each property} for i := 0 to propCnt - 1 do AList.Add(propList[i].Name + ': ' + propList[i].PropType^.Name); finally FreeMem(propList, sizeOf(PPropInfo) * propCnt); end; end; end; function GetPropertyList(AControl: TPersistent; AProperty: string): PPropInfo; var i: integer; props: PPropList; typeData: PTypeData; begin Result := nil; if (AControl = nil) or (AControl.ClassInfo = nil) then Exit; typeData := GetTypeData(AControl.ClassInfo); if (typeData = nil) or (typeData^.PropCount = 0) then Exit; GetMem(props, typeData^.PropCount * SizeOf(Pointer)); try GetPropInfos(AControl.ClassInfo, props); for i := 0 to typeData^.PropCount - 1 do begin with Props^[i]^ do if (Name = AProperty) then result := Props^[i]; end; finally FreeMem(props); end; end; procedure TFrmPropertyList.SpeedButton1Click(Sender: TObject); var c: integer; begin ListProperties(self, ListBox1.Items); for c := 0 to ComponentCount - 1 do begin ListBox1.Items.Add(EmptyStr); ListProperties(Components[c], ListBox1.Items); end; end; end.
Tip by Ralph Friedman