advantage of properties:
1 properties can be used in data binding, public data member can not.
2 data validation can be wrote inside setter method. easy to implement, also multithread feature.
3 the access level of getter and setter method can be restricted using public, protected and private key word
4 properties can be used in abstract interface.
5 indexers of properties is possible.
6 getter and setter methods should not be time consuming or complex method. Such as database processing is not recommended.
c# Use Properties Instead of Accessible Data Members
原文：http://www.cnblogs.com/williamwood/p/4135644.html