在SharePoint Web部件中，如何在运行时设置Web部件的列表？

I have a Contact List web part I developed that is dependent on a custom list I created, also called Contact List. But instead of the web part ALWAYS requiring a list called Contact List whenever the web part is added to a page, I want it so I can add the web part to a page THEN set which list I want it to use. I guess I am asking how do you create custom properties for a web part, much like the baked-in properties of web parts you get when you click on the web part and then click Modify Shared Web Part.I have a Contact List web part I developed that