泛型委托的用武之地

冒泡排序大家都知道，例如一个整形数组，可以用冒泡排序来使它按从小到大的顺序排序，

但它仅限于了按整形数组来排序，如何做到按任意类型进行排序呢，例如按一个类的某个属性进行排序?

 

举例说明:定义一组以类MEmployee为元素的数组，按MEmployee的Salary属性进行排序，类似的可以引伸为对其他类型的比较

 

        -----------元素类定义----------------

        public class MEmployee
        {
            public string Name { get; private set; }
            public decimal Salary { get; private set; }

            public MEmployee(string name, decimal salary)
            {
                this.Name = name;
                this.Salary = salary;
            }

            public override string ToString()
            {
                return string.Format("{0},{1:C}", Name, Salary);
            }

            public static bool CompareSalary(MEmployee e1, MEmployee e2)      //定义一个静态的比较函数
            {
                return e1.Salary < e2.Salary;
            }
        }

 

      -------------比较类定义---------------------

        //BubbleSorter现在已经是一个通用的排序类了,这里委托起到了关键的作用

        public class BubbleSorter
        {

            //该函数接收两个参数,第一个为泛型数组参数，第二个是系统自定义的Func委托，它接收两参数，返回bool类型
            public static void Sort<T>(IList<T> sortArray,Func<T,T,bool> comparison)
            {
                for (int i = 0; i < sortArray.Count; i++)
                {
                    for (int j = i + 1; j < sortArray.Count; j++)
                    {
                        if (comparison(sortArray[j],sortArray[i]))   //调用委托进行大小比较
                        {
                            T temp =sortArray[i];
                            sortArray[i] = sortArray[j];
                            sortArray[j] = temp;
                        }
                    }
                }
            }
        }

       --------------测试代码--------------

        private void button_测试委托3_Click(object sender, EventArgs e)
        {
            MEmployee[] employees =
            {
                new MEmployee("Ronaldo",40000),
                new MEmployee("Rivaldo",35000),
                new MEmployee("CRonaldo",80000)
            };
            BubbleSorter.Sort<MEmployee>(employees, MEmployee.CompareSalary);
            foreach (MEmployee oTmp in employees)
            {
                Console.WriteLine(oTmp.ToString());
            }
        }

       --------------测试结果--------------