How do you set Textbox.Readonly to true for all values in the list?

Hi, I'm having a problem with setting Textbox.Readonly to true for all values in the list.
Can anyone have an idea about how to do so?
It says "undefined variable"

You put the wrong blocks in the list.

Instead of .Text blocks, use the component block TextBoxthWord from the end of each component's block pallette.
For examples, see