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));