How to: Set a security zone for a ClickOnce application
When setting code access security permissions for a ClickOnce application, you need to start with a base set of permissions on the Security page of the Project Designer.
In most cases, you can also choose the Internet zone which contains a limited set of permissions, or the Local Intranet zone which contains a greater set of permissions. If your application requires custom permissions, you can do so by choosing the Custom security zone. For more information about setting custom permissions, see How to: Set Custom Permissions for a ClickOnce Application.
To set a security zone
With a project selected in Solution Explorer, on the Project menu click Properties.
Click the Security tab.
Select the Enable ClickOnce Security Settings check box.
Select the This is a partial trust application option button.
The controls in the ClickOnce security permissions section are enabled.
In the Zone your application will be installed from drop-down list, select a security zone.