VirtualDirectory Property
Specifies a directory relative to a Web server where a Web application folder is installed on a target computer. By default the folder is placed directly beneath the Web root in a directory with the same name as the deployment project.
Note
To install to the Web root directory, change the VirtualDirectory property to null (delete the default value).
Remarks
The VirtualDirectory property cannot contain the following characters: ?, |, <, >, :, ", or *. The path may contain either forward slashes (/) or backward slashes (\), but not both.