I have created multiple user controls in my project and what I need to do is to be able to switch between them on a panel control.
for example, if the user click button1
You need to instantiate a new MyProject.Modules.Masters.
MyProject.Modules.Masters myMasters = new MyProject.Modules.Masters()
panel1.Controls.Add(myMasters);
This will only add a new control to panel1. If you also want to clear everything out of the panel before adding the control like you said in the question, call this first:
panel1.Controls.Clear();