When will app.config be created?

[Guest]

I have just created a Window application to show a message when I click a
button on a Window Form. No app.config is created. What kind of items will
cause the creation of app.config?

 

[Guest]

I know one case of those:
When you save setting of My.Settings.

 

[Phill W.]

I have just created a Window application to show a message when I click a
button on a Window Form. No app.config is created.

That's because, by default, you don't need one. Applications are
perfectly happy to run without one.

What kind of items will cause the creation of app.config?

Add an "Application Configuration file" to your project.

HTH,
Phill W.