VBA Microsoft Programming Accessing Variables across slides

in the slide 2 code I have declared the variable as public

PublicUserNameAsString

then I have set the value of this inside my button click function

PublicSubSaveName_Click()
UserName=TextBox1.Value
EndSub

I am trying to access the variable on a later slide by using

Slide2.UserName

However I am having no luck, can anyone advise me on where I am going wrong?

Thank you in advance