The error message '' y 'is not declared. " at vb.net

Question

I have a strange problem. I have code in Visual Studio 2012 express edition in a WPF application written with VisualBasic.Net.

Private Sub txtColProvGenCompany_TextChanged(sender As Object, e As TextChangedEventArgs) Handles txtColProvGenCompany.TextChanged ProvNewEditing() End Sub 

But when I try to run the application, it says that it cannot build, because y from txtConProvGenCompan***y***.TextChanged . Error message

y not declared. it may not be available due to its level of protection

and shows only the character underlined in my code.

any ideas?