share a user control across projects in a solution

I used this article to figure this out. Here is my summary of the article, for what I did for a recent solution.

You can keep the user controls to the project you initially created them in, but use then in other projects of the same solution by adding a pre-build event to the project where you want to also use the controls. You can add such an event by going to the Properties of the project (right click on the project in solution explorer) where you want to add the controls, and go to the Build Events tab. You type a command to copy the controls from the project they were created in, to the project you want them to be used in. Then, before running a build on this project, if you have directed the control to be copied into a directory, you do need to make sure that directory exists. For DOM at this point, I created a folder called UserControls into whatever project I was adding the controls to. Finally, after you run the build, make sure you include the folder and/or the controls that were just copied over in the project they were just copied into.