How to: Set the Copy Local Property of a Reference

Programming, error messages and sample code
The Copy Local property (corresponding to CopyLocal) determines whether a reference is copied to the local bin path. At run time, a reference must be located in either the Global Assembly Cache (GAC) or the output path of the project. If this property is set to true, the reference is copied to the output path of the project at run time.

If you deploy/copy an application that contains a reference to a custom component that is registered in the GAC, the component will not be deployed/copied with the application, regardless of the Copy Local setting. For more information, see Project References.
 
The Copy Local property is set in the Reference Properties dialog box, available from the References pane of the Project Designer.

To set the Copy Local property to True or False
 1.   In Solution Explorer, click the Show All Files button to display the References node.
 2.  Open the References node for the project.
 3.  Right-click a reference in the References list, and click Properties.
 4.  The properties associated with that reference appear in a list in the Properties window.
 5.  Select Copy Local from the left-hand column, and then click the arrow in the right-hand column to change the value to True or False.