using System; using System.Collections.Generic; using System.Text; using System.Linq; using System.Linq.Expressions; using Xunit; namespace LinqStudy.Test.LinqToObject { /// /// 排序操作符 /// 数据源为null时,均引发ArgumentNullException异常 /// public class OrderTest { #region OrderBy /// /// OrderBy:升序排序(从小到大);延迟执行 /// [Fact] public void OrderBy_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=33 }, new Person(){ Id = 3, Name = "李四", Age=65 }, new Person(){ Id = 2, Name = "王五", Age=17 }, }; var oprationItem = peoples.OrderBy(p => p.Id); var firtId = oprationItem.First().Id; var lastId = oprationItem.Last().Id; Assert.Equal(1,firtId); Assert.Equal(3, lastId); } /// /// 延迟执行 /// [Fact] public void OrderBy_Delay_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=33 }, new Person(){ Id = 3, Name = "李四", Age=65 }, new Person(){ Id = 2, Name = "王五", Age=17 }, }; var oprationItem = peoples.OrderBy(p => p.Id); var addItem = new Person() { Id = 4, Name = "赵立", Age = 87 }; peoples.Add(addItem); var firtId = oprationItem.First().Id; var lastId = oprationItem.Last().Id; Assert.Equal(1, firtId); Assert.Equal(4, lastId); } /// /// 重载:自定义Comparable比较器 /// [Fact] public void OrderBy_CustomComparable_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=33 }, new Person(){ Id = 3, Name = "李四", Age=65 }, new Person(){ Id = 2, Name = "王五", Age=17 }, }; var oprationItem = peoples.OrderBy(p => p, new PersonComparer()); var firtId = oprationItem.First().Id; var lastId = oprationItem.Last().Id; Assert.Equal(1, firtId); Assert.Equal(3, lastId); } #endregion #region OrderByDescending /// /// OrderByDescending:降序排序(从大到步);延迟执行 /// [Fact] public void OrderByDescending_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=33 }, new Person(){ Id = 3, Name = "李四", Age=65 }, new Person(){ Id = 2, Name = "王五", Age=17 }, }; var oprationItem = peoples.OrderByDescending(p => p.Id); var firtId = oprationItem.First().Id; var lastId = oprationItem.Last().Id; Assert.Equal(3, firtId); Assert.Equal(1, lastId); } /// /// 延迟执行 /// [Fact] public void OrderByDescending_Delay_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=33 }, new Person(){ Id = 3, Name = "李四", Age=65 }, new Person(){ Id = 2, Name = "王五", Age=17 }, }; var oprationItem = peoples.OrderByDescending(p => p.Id); var addItem = new Person() { Id = 4, Name = "赵立", Age = 87 }; peoples.Add(addItem); var firtId = oprationItem.First().Id; var lastId = oprationItem.Last().Id; Assert.Equal(4, firtId); Assert.Equal(1, lastId); } /// /// 重载:自定义Comparable比较器 /// [Fact] public void OrderByDescending_CustomComparable_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=33 }, new Person(){ Id = 3, Name = "李四", Age=65 }, new Person(){ Id = 2, Name = "王五", Age=17 }, }; var oprationItem = peoples.OrderByDescending(p => p, new PersonComparer()); var firtId = oprationItem.First().Id; var lastId = oprationItem.Last().Id; Assert.Equal(3, firtId); Assert.Equal(1, lastId); } #endregion #region ThenBy /// /// ThenBy:按次要关键字,进行升序排序(从小到大);延迟执行 /// [Fact] public void ThenBy_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=44 }, new Person(){ Id = 1, Name = "李四", Age=33 }, new Person(){ Id = 2, Name = "王五", Age=22 }, new Person(){ Id = 2, Name = "赵立", Age=11 }, }; //先按Id排序,Id相同的,再按年龄排序。 var oprationItem = peoples.OrderBy(p => p.Id).ThenBy(p => p.Age).Select(p => p.Name); var expected = new List() { "李四", "张三", "赵立", "王五" }; Assert.Equal(expected, oprationItem); } /// /// 延迟执行 /// [Fact] public void ThenBy_Delay_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=44 }, new Person(){ Id = 1, Name = "李四", Age=33 }, new Person(){ Id = 2, Name = "王五", Age=22 }, new Person(){ Id = 2, Name = "赵立", Age=11 }, }; var oprationItem = peoples.OrderBy(p => p.Id).ThenBy(p => p.Age); var addItme = new Person() { Id = 1, Name = "刘能", Age = 2 }; peoples.Add(addItme); var actual = oprationItem.Select(p => p.Name).ToList(); var expected = new List() { "刘能", "李四", "张三", "赵立", "王五" }; Assert.Equal(expected, actual); } /// /// 重载:自定义Comparable比较器 /// [Fact] public void ThenBy_CustomComparable_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=44 }, new Person(){ Id = 1, Name = "李四", Age=33 }, new Person(){ Id = 2, Name = "王五", Age=22 }, new Person(){ Id = 2, Name = "赵立", Age=11 }, }; var oprationItem = peoples.OrderBy(p => p, new PersonComparer()).ThenBy(p=>p.Age,Comparer.Default); var actual = oprationItem.Select(p => p.Name).ToList(); var expected = new List() {"李四", "张三", "赵立", "王五" }; Assert.Equal(expected, actual); } #endregion #region ThenByDescending /// /// ThenByDescending:按次要关键字,进行降序排序(从大到小);延迟执行 /// [Fact] public void ThenByDescending_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=44 }, new Person(){ Id = 1, Name = "李四", Age=33 }, new Person(){ Id = 2, Name = "王五", Age=22 }, new Person(){ Id = 2, Name = "赵立", Age=11 }, }; //先按Id排序,Id相同的,再按年龄排序。 var oprationItem = peoples.OrderBy(p => p.Id).ThenByDescending(p => p.Age).Select(p => p.Name); var expected = new List() {"张三","李四","王五", "赵立"}; Assert.Equal(expected, oprationItem); } /// /// 延迟执行 /// [Fact] public void ThenByDescending_Delay_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=44 }, new Person(){ Id = 1, Name = "李四", Age=33 }, new Person(){ Id = 2, Name = "王五", Age=22 }, new Person(){ Id = 2, Name = "赵立", Age=11 }, }; var oprationItem = peoples.OrderBy(p => p.Id).ThenByDescending(p => p.Age); var addItme = new Person() { Id = 1, Name = "刘能", Age = 2 }; peoples.Add(addItme); var actual = oprationItem.Select(p => p.Name).ToList(); var expected = new List() { "张三", "李四", "刘能", "王五","赵立" }; Assert.Equal(expected, actual); } /// /// 重载:自定义Comparable比较器 /// [Fact] public void ThenByDescending_CustomComparable_Test() { List peoples = new List() { new Person(){ Id = 1, Name = "张三", Age=44 }, new Person(){ Id = 1, Name = "李四", Age=33 }, new Person(){ Id = 2, Name = "王五", Age=22 }, new Person(){ Id = 2, Name = "赵立", Age=11 }, }; var oprationItem = peoples.OrderBy(p => p, new PersonComparer()).ThenByDescending(p => p.Age, Comparer.Default); var actual = oprationItem.Select(p => p.Name).ToList(); var expected = new List() { "张三","李四", "王五", "赵立",}; Assert.Equal(expected, actual); } #endregion } }