Door keyDownEvent & Hardware KeyDown

I've an editable combobox, which allow user to enter some text & hit "enter" to search, then the combobox will dropdown with the value (working fine).

What I try to do now is use the Hardware.Keydown(13) to simulate "Enter" when user click on search button, but seems like the keydown even does not capture by the keyDownEvent :sign0085:

Hi, why use KeyDown? KeyDown simulate a Pressing without up the key... KeyPress can be a better way I think...
You can maybe use KeyDown and KeyUp in same time...
KeyPress is KeyDown and KeyUp, when we type a letter we press a key and we up the key for write a letter...

We can use KeyDown on shift for type a uppercase letter while the shift key it's not up...

Thanks. I actually tried both KeyPress & KeyDown & doesn't work.