Как изменить значение свойства компонента по имени?
01.01.2007
function GetProperty(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 TForm1.Button1Click(Sender: TObject); var propInfo: PPropInfo; begin PropInfo := GetProperty(Button1.Font, 'Name'); if PropInfo <> nil then SetStrProp(Button1.Font, PropInfo, 'Arial'); end;
Взято из https://www.lmc-mediaagentur.de/dpool
You can use RTTI to do this. Here is how to change a particular component:
procedure TForm1.BtnClick(Sender: TObject); var p: PPropInfo; f: TFont; begin f := TFont.Create; {Setup the font properties} f.Name := 'Arial'; p := GetPropInfo(Sender.ClassInfo, 'Font'); if Assigned(p) then SetOrdProp(Sender, p, Integer(f)); f.Free; end;
To get at all the forms loop through the Screen global variable. For each form loop through its Components list calling the above procedure (or something close). If you only create your components at design time that is it. If you create some at runtime and the owner is not the form, then for each component loop through its Components list recursively to get at all the owned components.
Tip by Jeff Overcash
Взято из https://www.lmc-mediaagentur.de/dpool
I am building a routine that checks our forms for validity before deploying them. I would like to use some kind of structure that tests if a component type has access to a certain property, something like: " if (self.Controls[b] has Tag) then ...". Can anyone offer suggestions?
Here's an example of setting a string property for a component if it exists and another for an integer property:
{ Copyright © 1999 by Delphi 5 Developer's Guide - Xavier Pacheco and Steve Teixeira } procedure SetStringPropertyIfExists(AComp: TComponent; APropName: String; AValue: String); var PropInfo: PPropInfo; TK: TTypeKind; begin PropInfo := GetPropInfo(AComp.ClassInfo, APropName); if PropInfo <> nil then begin TK := PropInfo^.PropType^.Kind; if (TK = tkString) or (TK = tkLString) or (TK = tkWString) then SetStrProp(AComp, PropInfo, AValue); end; end; procedure SetIntegerPropertyIfExists(AComp: TComponent; APropName: String; AValue: Integer); var PropInfo: PPropInfo; begin PropInfo := GetPropInfo(AComp.ClassInfo, APropName); if PropInfo <> nil then begin if PropInfo^.PropType^.Kind = tkInteger then SetOrdProp(AComp, PropInfo, AValue); end; end;
Tip by Xavier Pacheco