CODEWITHSUNDEEP
delphidelphi-10.1-berlin
Steve88
Steve88

Reputation: 2416

Set component focus with RTTI

Is it possible to reach any control Focus property through Rtti? What I want is to set its value to True if the control is Empty. Any help would be greatly appreciated.

procedure SetFirstEmptyCtrlFocused;

  function HasTextProp(aControl: TControl): Boolean;
  var
    Ctx: TRttiContext;
    Prop: TRttiProperty;
  begin
    Prop := lCtx.GetType(aControl.ClassType).GetProperty('Text');
    Result := (Prop <> nil) and (Prop.Visibility in [mvPublic, mvPublished]) 
      and (Prop.GetValue(aControl).ToString = '');
  end;

var
  ObjList: TObjectList<TControl>;
  objIdx: Integer;
  Ctrl: TControl;

begin
  ObjList := TObjectList<TControl>.Create;
  ObjList.Add(cxTextEdit1);
  ObjList.Add(cxDateEdit1);
  ObjList.Add(cxTextEdit2);

  for objIdx := 0 to lObjList.Count -1 do
  begin
    Ctrl := lObjList.Items[objIdx];

    if HasTextProp(lCtrl) then
    begin
      SetCtrlFocused //...??
      Break;
    end;
  end;   
end;

Upvotes: 1

Views: 164

Answers (1)

Uwe Raabe
Uwe Raabe

Reputation: 47879

Not every TControl can receive the focus, only TWinControl can. So instead of TControl use TWinControl and use its method SetFocus:

procedure SetFirstEmptyWinCtrlFocused;

  function HasTextProp(aControl: TWinControl): Boolean;
  var
    Ctx: TRttiContext;
    Prop: TRttiProperty;
  begin
    Prop := Ctx.GetType(aControl.ClassType).GetProperty('Text');
    Result := (Prop <> nil) and (Prop.Visibility in [mvPublic, mvPublished]) 
      and (Prop.GetValue(aControl).ToString = '');
  end;

var
  ObjList: TObjectList<TWinControl>;
  objIdx: Integer;
  Ctrl: TWinControl;

begin
  ObjList := TObjectList<TWinControl>.Create;
  ObjList.Add(cxTextEdit1);
  ObjList.Add(cxDateEdit1);
  ObjList.Add(cxTextEdit2);

  for objIdx := 0 to lObjList.Count -1 do
  begin
    Ctrl := lObjList.Items[objIdx];

    if HasTextProp(Ctrl) then
    begin
      Ctrl.SetFocus;
      Break;
    end;
  end;   
end;

Upvotes: 3

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