I have been using C# in conjunction with Silverlight, and I am kind of confused as to the process of creating custom controls.

I watched several videos which showed me how to create a custom control in Expression Blend, which I then went and did, but I am at a loss as to how to give my control some real functionality. I have seen a few tutorials online that talk about this, but they all seem very vague, way over my head, or very different from each other.

Does anyone have any experience with this and could give me some ideas?