When I create new item -> sub layout it will create web user control. I need change the template structure of web user control's code behind file (using should come outside of namespace) when it creating.
The default templates for the Sitecore Items is in the following folder:
C:\Users\<username>\AppData\Local\Microsoft\VisualStudio\12.0\Extensions\<install-id>\ItemTemplates\Sitecore
Extract Sublayouts.zip file from Sublayouts folder, move the using
statement to outside the namespace in Sublayout.ascx.cs
and re-pack the zip file. Restart Visual Studio and the changes should take effect.