How to prevent the code execution if a textbox is empty?

Question

I want to prevent the code execution if user leave a textbox empty

If tx01.Value = "" Then Exit Sub
If tx01.Value = vbNullString Then Exit Sub  //  also tried

But user can simply write a space (or any number of spaces) and - prevention doesn't work.
I need characters in this box (numeric and nonNumeric), but not only spaces.
How can I do this, pls ?

Answer 1

something like

if trim(tx01.Value) = "" then Exit sub

Trim removes leading and trailing whitespace characters.

Answer 2

Try adding a Trim() in the textbox value check.