How to get combobox and radio button ''out of focus''?

Question

I'm trying to make an app which reads keys from the keyboard. When I press a key, the program adds it to an array and then I do what I want. I'm not writing in an Edit control. I'm directly pressing buttons on the keyboard, since I want to be able to work with other inputs like readers, that simulate input like keyboards.

Now I added a combo box and radio buttons, with which I'm going to add new stuff in the future. I tried the app again after I added the components and the program doesn't read the keys anymore, since it tries to write inside the combo box. If I press outside of the combo box, or choose an option, nothing happens, and it keeps trying to write in it.

If I press the radio button, the program no longer tries to write in the combo box, but it still doesn't read keys from the keyboard, probably because the focus now is on the radio button.

If I make the combo box property Enabled := false and I don't press a radio button, then it works again.

I think that the problem is that the program has it's 'focus' on the components. I looked into the properties of the components, and I don't see any property that could help.

Is there a way with code or a property on the components to make the components not take the focus of the program? I work with TRadioButton, TComboBox or TAdvComboBox.

I use the FormKeyDown event to get the key information.

procedure

TfrmConfigCheck.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
     
end;

Answer 1

You need to set the KeyPreview property on the form to True.

If KeyPreview is set to False, then the form's onKeyDown event isn't called when some components such as a TComboBox have focus.

But if you set the KeyPreview property to True, then the form's onKeyDown event is called every time a key is pressed down no matter what component is focused on the form.

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And regarding your other issue in the comments, you can't set the TComboBox to be readonly, but you can set the style property to csDropDownList which is kind of a readonly mode since a user can't enter any detai

Answer 2

Under your application form event TForm.OnShow put Form1.SetFocus; You can always do this under onClick, onEnter, etc of any control to return the focus to the form.