C# Linq中的自定义排序-编程知识

C# Linq中的自定义排序

1.开发过程中，会遇到OrderBy/OrderByDescending排序无法满足的情况，此时就需要自定义排序，按照想要的排序规则取排序，比如订单的状态等等。

2.自定义泛型比较器代码如下：

    /// <summary>/// 自定义泛型比较器(用于自定义排序)/// </summary>public class CustomComparer<T> : IComparer<T>{/// <summary>/// 排好的排序列表/// </summary>private List<T> _preferenceList;/// <summary>/// 构造函数/// </summary>/// <param name="preferenceList">排好的排序列表</param>public CustomComparer(List<T> preferenceList){_preferenceList = preferenceList ?? new List<T>();}/// <summary>/// 执行比较/// </summary>/// <param name="x"></param>/// <param name="y"></param>/// <returns></returns>public int Compare(T x, T y){if (!_preferenceList.Any()){return DefaultCompare(x, y);}var index_x = _preferenceList.IndexOf(x);var index_y = _preferenceList.IndexOf(y);return index_x.CompareTo(index_y);}/// <summary>/// 默认比较/// </summary>private int DefaultCompare(T x, T y){return string.Compare(x.ToString(), y.ToString(), false, CultureInfo.CurrentCulture);}}

3.使用(此处以自定义用户名称作为数组去排序):

var users = new List<User>()
{new User() { Id = 1,UserName = "张三",Password = "123456",Age = 18,Sex = 0},new User() { Id = 2,UserName = "李婷婷",Password = "123456",Age = 28,Sex = 1},new User() { Id = 3,UserName = "王五",Password = "123456",Age = 19,Sex = 0},new User() { Id = 4,UserName = "赵灵儿",Password = "123456",Age = 21,Sex = 1},new User() { Id = 5,UserName = "韩企",Password = "123456",Age = 22,Sex = 0},new User() { Id = 6,UserName = "宋华",Password = "123456",Age = 20,Sex = 0},new User() { Id = 7,UserName = "王斌",Password = "123456",Age = 21,Sex = 0}
};var orderbys = new List<string>()
{"李婷婷","赵灵儿","张三","王五","韩企","宋华","王斌"
};var result = users.AsQueryable().OrderByDescending(s=>s.UserName, new CustomComparer<string>(orderbys));