TMemo instead of TLabel

[karl Jonson 0]

Hi,
I'm using a procedure which uses a TLabel parameter & sets the caption of the label:

 

prcedure GetString(param1: string; param2:string; myLabel: TLabel);
Begin
  myLabel.caption := GetDescription()
End

 
Everything works fine & I don't want to break it as it's called from different places.
Now I'd like to be able to sometimes pass it TMemo and display multiple lines in the TMemo component:

 

  myMemo.lines.Add(GetDescription());

I'd like to be able to say if component is TLabel then do this but if it's TMemo then do that.

TIA

Edited July 20, 2022 by karl Jonson
explanation

[Uwe Raabe 2057]

procedure GetString(param1: string; param2:string; myLabel: TLabel); overload;
Begin
  myLabel.caption := GetDescription();
End;

procedure GetString(param1: string; param2:string; myMemo: TMemo); overload;
Begin
  myMemo.lines.Add(GetDescription());
End;

 

[limelect 48]

If I understand your need add a flag to 

GetDescription(FLAG: boolean) so your function will know where it came from

Memo.lines.add(getDescription(true)) or label.caption:=getdescription(false)

Edited July 20, 2022 by limelect

[Remy Lebeau 1398]

8 hours ago, karl Jonson said:

Now I'd like to be able to sometimes pass it TMemo and display multiple lines in the TMemo component:

  myMemo.lines.Add(GetDescription());

I'd like to be able to say if component is TLabel then do this but if it's TMemo then do that.

You can use the 'is' operator for that purpose, eg:

procedure GetString(param1: string; param2: string; myControl: TControl);
begin
  if myControl is TLabel then
    TLabel(myControl).Caption := GetDescription()
  else if myControl is TMemo then
    TMemo(myControl).Lines.Add(GetDescription())
  else
    ...;
end;

Alternatively, every TControl has a Caption (and Text) property, even if it is not published. You can take advantage of that, eg:

type
  TControlAccess = class(TControl)
  end;

procedure GetString(param1: string; param2: string; myControl: TControl);
begin
  if myControl is TMemo then
    TMemo(myControl).Lines.Add(GetDescription())
  else
    TControlAccess(myControl).Caption := GetDescription();
end;

Or, you can use RTTI instead, eg:

procedure GetString(param1: string; param2: string; myControl: TControl);
var
  Ctx: TRttiContext;
  Typ: TRttiType;
  Prop: TRttiProperty;
begin
  Ctx := TRttiContext.Create;
  try
    Typ := Ctx.GetType(myControl.ClassType);
    Prop := Typ.GetProperty('Caption');
    if (Prop <> nil) and (Prop.Visibility = mvPublished) then
    begin
      Prop.SetValue(myControl, GetDescription());
      Exit;
    end;
    Prop := Typ.GetProperty('Text');
    if (Prop <> nil) and (Prop.Visibility = mvPublished) then
    begin
      Prop.SetValue(myControl, GetDescription());
      Exit;
    end;
    Prop := Typ.GetProperty('Lines');
    if (Prop <> nil) and (Prop.Visibility = mvPublished) then
    begin
      (Prop.GetValue(myControl).AsObject() as TStrings).Add(GetDescription());
      Exit;
    end;
    ...
  finally
    Ctx.Free;
  end;
end;