List<T> .Orderby 没法排序？

List<T> .Orderby 无法排序？？？
            MyClass tmpClass = new MyClass();
            List<MyClass> tmpList = new List<MyClass>();
            tmpClass.MyID = "5";
            tmpClass.RandomCode = "555";
            tmpList.Add(tmpClass);

            tmpClass = new MyClass();
            tmpClass.MyID = "3";
            tmpClass.RandomCode = "333";
            tmpList.Add(tmpClass);

            tmpClass = new MyClass();
            tmpClass.MyID = "1";
            tmpClass.RandomCode = "111";
            tmpList.Add(tmpClass);

            tmpClass = new MyClass();
            tmpClass.MyID = "4";
            tmpClass.RandomCode = "444";
            tmpList.Add(tmpClass);

            tmpClass = new MyClass();
            tmpClass.MyID = "2";
            tmpClass.RandomCode = "222";
            tmpList.Add(tmpClass);

            tmpList.OrderBy(p => p.MyID).ToList();
            
            查看结果，排序还是 5 3 1 4 2  ?

我想把里面的 排序成 12345 请问不能排序是什么原因
------解决思路----------------------
tmpList = tmpList.OrderBy(p => p.MyID).ToList();
------解决思路----------------------

引用:

tmpList = tmpList.OrderBy(p => p.MyID).ToList();

或tmpList.Sort((x,y)=>{ return x.MyID.CompareTo(y.MyID); });