一个采用MVVM模框架设计的WPF自定义组合框控件，能够显示多个选择项。主要目的是让读者学习采用MVVM模式设计程序的思路。-A design framework using MVVM die WPF custom combo box control, can display multiple options. The main purpose is to let readers learn using MVVM pattern design ideas of the program.

Design program written in VC primitives, can create a new pattern primitives,