Is it possible to access a TButton using tag?
I hope to access a T开发者_运维百科Button using tag. IS it possible?
for example, I hope set the caption of a TButton (button1 has tag 3) as 'aaa', I know I can use
button1.caption:='aaa';
but I hope to use tag '3' to access the tbutton and set the string value 'aaa'.
Welcome any comment
Thanks
interdev
procedure TForm1.ChnCaptionByTag(SearchTag: integer; NewCpt: string);
var
i: Integer;
begin
for i := 0 to ComponentCount - 1 do
if Components[i] is TButton then
begin
if TButton(Components[i]).Tag = SearchTag then
TButton(Components[i]).Caption := NewCpt;
end;
end;
There is no direct way to do
ButtonByTag(3).Caption := 'aaa';
You can search through a form's components looking for something with a tag of 3:
var C: TComponent;
for C in Self.Components do
if C is TCustomButton then
if C.Tag = 3 then
(C as TCustomButton).Caption := 'aaa'
But note that you could have plenty of components with the same tag, it's not guaranteed unique.
I think this should work:
procedure TForm1.SetCaption(iTag: Integer; mCaption: String);
var
i: Integer;
begin
for i:= 0 to controlcount-1 do
if controls[i] is TButton then
if TButton(controls[i]).Tag = iTag then
TButton(controls[i]).Caption := mCaption;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
SetCaption(3,'aaa');
end;
Well, right now the Tag property is the same size as a Pointer, so you could, but you need to describe a bit more of what it is you'd like to do.
I'm not positive that this is going to continue to be the case moving into 64-bit Delphi, but I think that's the case too.
Edit: Yes, TComponent.Tag
should be a NativeInt
in future versions. References: Barry Kelly, Alexandru Ciobanu
procedure TForm1.ChangeCaptionByTag(const SearchTag: integer; const NewCaption: string);
var i: Integer;
begin
for i in Components do
if Components[i] is TButton then
if (Components[i] as TButton).Tag = SearchTag then
begin
(Components[i] as TButton).Caption := NewCaption;
Break;
end;
end;
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