How to prevent user to wirte in a comboBox or a textBox

Question

Hello

How to prevent user to write in comboBox? I just need to allow the user to select from the list.
If I  set DropDownStyle property to DropDownList, this will work, but I want to keep DropDownStyle = DropDown.

Also, How to prevent a user to write in a textbox without disable it. I have a textbox which will display an output. I need to keep it enabled but not allowing the user to write in.

I tried to set locked property to true as well, but this didn't work. Any idea?