解决方法
http://msdn.microsoft.com/en-us/library/b0zbh7b6.aspx
This method uses Array.sort,which uses the QuickSort algorithm. This implementation performs an unstable sort; that is,if two elements are equal,their order might not be preserved. In contrast,a stable sort preserves the order of elements that are equal.
On average,this method is an O(n log n) operation,where n is Count; in the worst case it is an O(n ^ 2) operation.