Visual Studio: fix the References in a web site solution or .NET project

A solution can have references to multiple sub-projects. If you make some code changes on a sub-project but the changes do not seem to take effects on the project, the reference may have been broken.

To check the references in the solution, right click on the Web Site on the Solution Explorer. Select Property Pages on the menu.

In the Property Pages dialogue, select References from the listed items. Check on the lists of the references and make sure the Version of all the sub-projects have the values of Auto Update. If it is a specific version number, your changes of the sub-project will have not effect. To change it to Auto Update, use the Remove button to remove the sub-project from the list and then use the Add button to add it back.

You may also be able to add or remove the References from the Solution Explorer for projects. Just expand the project and look for the References item.