ToolStrip is very useful container control, but it has it’s default set of controls you can put onto it. What if you wanted to have, say DateTimePicker, or some totally custom control you have made? You can inherit it from ToolStripItem, override some methods and properties, but there is a much quicker way, if you don’t need any custom behaviour.
To illustrate this i created simple form with ToolStrip, and I embeded DateTimePicker into it, as you can se below (code follows)
As you can see, all the magic that happens is thanks to ToolStripControlHost class.