更新

LinqStudy.Test/LinqStudy.Test.csproj

@@ -20,10 +20,6 @@
 
   <ItemGroup>
     <Folder Include="ExpressionTree\" />
-    <Folder Include="LinqToDataSet\" />
-    <Folder Include="LinqToSQL\" />
-    <Folder Include="LinqToXml\" />
-    <Folder Include="Util\" />
   </ItemGroup>
 
   <ItemGroup>

LinqStudy.Test/LinqToObject/TypeConvertTest.cs

@@ -18,6 +18,7 @@ namespace LinqStudy.Test.LinqToObject
     /// </summary>
     public class TypeConvertTest 
     {
+        #region AsEnumeralbe 
         /// <summary>
         ///  AsEnumeralbe操作符:将IEnumerable<T>输入序列转换成IEnumerable<T>的输出序列
         ///  主要用于将一个实现了IEnumerable<T>接口的对象转换成一个标准的IEnumerable<T>接口对象。
@@ -33,7 +34,9 @@ namespace LinqStudy.Test.LinqToObject
 
             Assert.NotNull(students);
         }
+        #endregion
 
+        #region AsQueryable
         /// <summary>
         /// 主要应用与Linq to sql
         /// </summary>
@@ -42,7 +45,9 @@ namespace LinqStudy.Test.LinqToObject
         {
             //
         }
+        #endregion
 
+        #region OfType
         /// <summary>
         /// OfType：从序列中筛选指定类型的元素，并构建一个序列。
         /// </summary>
@@ -50,14 +55,16 @@ namespace LinqStudy.Test.LinqToObject
         public void OfType_Test()
         {
             //动态数组做为数据源
-            ArrayList ints = new ArrayList() { 1,"2",3,"4",5};
+            ArrayList ints = new ArrayList() { 1, "2", 3, "4", 5 };
 
             var values = from i in ints.OfType<int>()
                          select i;
 
-            Assert.Equal(new List<int>() { 1,3,5}, values.ToList());
+            Assert.Equal(new List<int>() { 1, 3, 5 }, values.ToList());
         }
+        #endregion
 
+        #region Cast
         /// <summary>
         /// Cast：将数据源中元素，强制转换成指定的类型。
         /// 数据源null或存在不能转换的元素，则异常。
@@ -70,7 +77,7 @@ namespace LinqStudy.Test.LinqToObject
 
             var values = ints.Cast<string>();
 
-            Assert.Equal(new List<string>() {"1","2","3","4","5"}, values.ToList());
+            Assert.Equal(new List<string>() { "1", "2", "3", "4", "5" }, values.ToList());
         }
 
         [Fact]
@@ -79,7 +86,7 @@ namespace LinqStudy.Test.LinqToObject
             //动态数组做为数据源
             ArrayList ints = null;
 
-            Assert.Throws<ArgumentNullException>(()=> {
+            Assert.Throws<ArgumentNullException>(() => {
                 ints.Cast<string>();
             });
         }
@@ -88,13 +95,15 @@ namespace LinqStudy.Test.LinqToObject
         public void Cast_InvalidCastException_Test()
         {
             //动态数组做为数据源
-            ArrayList ints = new ArrayList() { 1,"2",3,"4"};
+            ArrayList ints = new ArrayList() { 1, "2", 3, "4" };
 
             Assert.Throws<InvalidCastException>(() => {
                 ints.Cast<string>().ToList();
             });
         }
+        #endregion
 
+        #region ToList
         /// <summary>
         ///  ToList：将IEnumerable<T>转换为List<T>, 立即执行。
         ///  特别注意：此操作破坏"延迟执行"，变为立即执行；
@@ -103,7 +112,7 @@ namespace LinqStudy.Test.LinqToObject
         [Fact]
         public void ToList_Test()
         {
-            List<string> email = new List<string>() { "abc@163.com","bcd@126.com","111@163.com"};
+            List<string> email = new List<string>() { "abc@163.com", "bcd@126.com", "111@163.com" };
 
             var query = email.Where(q => q.Contains("@163.")).ToList();
 
@@ -145,43 +154,222 @@ namespace LinqStudy.Test.LinqToObject
             //元素对象不是同一个元素
             Assert.NotSame(persons, person2);
         }
+        #endregion
 
+        #region ToDictionary
+        /// <summary>
+        /// ToDictionar转换字典，立即执行并保存快照。
+        /// </summary>
+        [Fact]
+        public void ToDictionary_keySelector_Test()
+        {
+            List<Person> persons = new List<Person>()
+            {
+                new Person() {Id=1, Name="gaofeng",Age = 32 },
+                new Person() {Id=2, Name="zhangsan",Age = 25 },
+            };
 
+            var dic = persons.ToDictionary(p => p.Id);
 
-        private DataTable GetDataTable()
+            Assert.Equal(1, dic[1].Id);
+            Assert.Equal(2, dic[2].Id);
+        }
+
+        [Fact]
+        public void ToDictionary_keySelector_comparer_Test()
+        {
+            List<Person> persons = new List<Person>()
+            {
+                new Person() {Id=1, Name="gaofeng",Age = 32 },
+                new Person() {Id=2, Name="zhangsan",Age = 25 },
+            };
+
+            IEqualityComparer<Person> equal = new PersonEqual();
+
+            var dic = persons.ToDictionary<Person, int>(p => p.Id, EqualityComparer<int>.Default);
+
+            Assert.Equal("gaofeng", dic[1].Name);
+            Assert.Equal("zhangsan", dic[2].Name);
+        }
+
+        [Fact]
+        public void ToDictionary_keySelector_elementSelector_Test()
+        {
+            List<Person> persons = new List<Person>()
+            {
+                new Person() {Id=1, Name="gaofeng",Age = 32 },
+                new Person() {Id=2, Name="zhangsan",Age = 25 },
+            };
+
+            var dic = persons.ToDictionary(p => p.Id, s => s.Name);
+
+            Assert.Equal("gaofeng", dic[1]);
+            Assert.Equal("zhangsan", dic[2]);
+        }
+
+        [Fact]
+        public void ToDictionary_keySelector_elementSelector_comparer_Test()
+        {
+            List<Person> persons = new List<Person>()
+            {
+                new Person() {Id=1, Name="gaofeng",Age = 32 },
+                new Person() {Id=2, Name="zhangsan",Age = 25 },
+            };
+
+            var dic = persons.ToDictionary(p => p.Id, s => s.Name, EqualityComparer<int>.Default);
+
+            Assert.Equal("gaofeng", dic[1]);
+            Assert.Equal("zhangsan", dic[2]);
+        }
+
+        [Fact]
+        public void ToDictionary_ArgumentException_Test()
+        {
+            List<Person> persons = new List<Person>()
+            {
+                new Person() {Id=1, Name="gaofeng",Age = 32 },
+                new Person() {Id=1, Name="zhangsan",Age = 25 },
+            };
+
+            Assert.Throws<ArgumentException>(() => {
+                persons.ToDictionary(p => p.Id, s => s.Name);
+            });
+        }
+
+        [Fact]
+        public void ToDictionary_ArgumentNullException_Test()
+        {
+            List<Person> persons = new List<Person>()
+            {
+                new Person() {Id=1, Name=null,Age = 32 },
+                new Person() {Id=1, Name="zhangsan",Age = 25 },
+            };
+
+            Assert.Throws<ArgumentNullException>(() => {
+                persons.ToDictionary(p => p.Name, s => s.Name);
+            });
+        }
+
+        [Fact]
+        public void ToDictionary_DataSource_NullException_Test()
+        {
+            List<Person> persons = null;
+
+            Assert.Throws<ArgumentNullException>(() => {
+                persons.ToDictionary(p => p.Name, s => s.Name);
+            });
+        }
+        #endregion
+
+        #region ToLookup
+
+        /// <summary>
+        /// ToLookup：根据指定的键选择器函数从IEnumerable<T>创建Lookup<T>
+        /// Lookup<T>对象表示一个一对多的字典，定义了一个由键和序列组成的元组，类似GroupJoin返回的结果。
+        /// </summary>
+        [Fact]
+        public void ToLookup_Test()
+        {
+            var persons = new List<Employee>()
+            {
+                new Employee(){ Id=1, Name="gaofeng",Emails=new List<string>(){"a1@163.com","a2@163.com","a3@163.com"} },
+                new Employee(){ Id=1, Name="zhangsan",Emails=new List<string>(){ "b1@163.com", "b2@163.com", "b3@163.com" } },
+
+                new Employee(){ Id=2, Name="gaofeng2",Emails=new List<string>(){"c1@163.com","c2@163.com","c3@163.com"} },
+                new Employee(){ Id=2, Name="zhangsan2",Emails=new List<string>(){ "d1@163.com", "d2@163.com", "d3@163.com" } },
+            };
+
+            var lookup = persons.ToLookup(q => q.Id);
+            var group2 = lookup[2];
+            var group2_count = group2.Count();
+
+            Assert.Equal(2,group2_count);
+        }
+
+        [Fact]
+        public void ToLookup_keySelector_comparer_Test()
         {
+            var persons = new List<Employee>()
+            {
+                new Employee(){ Id=1, Name="gaofeng",Emails=new List<string>(){"a1@163.com","a2@163.com","a3@163.com"} },
+                new Employee(){ Id=1, Name="zhangsan",Emails=new List<string>(){ "b1@163.com", "b2@163.com", "b3@163.com" } }
+            };
+
+            var lookup = persons.ToLookup(q => q.Id,EqualityComparer<int>.Default);
+            var group1_firstEmail = lookup[1].FirstOrDefault().Emails.FirstOrDefault() ;
 
-            DataTable dt=new DataTable();
+            Assert.Equal("a1@163.com", group1_firstEmail);
-            DataColumn col_id=new DataColumn("Id");
+        }
-            col_id.AllowDBNull=false;
-            col_id.AutoIncrementSeed=1;
-            col_id.AutoIncrement=true;
-            col_id.AutoIncrementStep=1;
-            col_id.DataType=typeof(int);
 
-            DataColumn col_name=new DataColumn("Name");
+        [Fact]
-            col_name.AllowDBNull=true;
+        public void ToLookup_keySelector_elementSelector_Test()
-            col_name.AutoIncrement=false;
+        {
-            col_name.DataType=typeof(string);
+            var persons = new List<Employee>()
-            col_name.DefaultValue=string.Empty;
+            {
+                new Employee(){ Id=1, Name="gaofeng",Emails=new List<string>(){"a1@163.com","a2@163.com","a3@163.com"} },
+                new Employee(){ Id=1, Name="zhangsan",Emails=new List<string>(){ "b1@163.com", "b2@163.com", "b3@163.com" } }
+            };
 
-            DataColumn col_age=new DataColumn("Age");
+            var lookup = persons.ToLookup(q => q.Id, e=>e.Emails);
-            col_age.AllowDBNull=false;
+            var group1_Emails = lookup[1].FirstOrDefault();
-            col_age.AutoIncrement=false;
+            var group1_Emails_first = group1_Emails.FirstOrDefault();
-            col_age.DataType=typeof(int);
+
-            col_age.DefaultValue=20;
+            Assert.Equal("a1@163.com", group1_Emails_first);
+        }
+
+        [Fact]
+        public void ToLookup_keySelector_elementSelector_comparer_Test()
+        {
+            var persons = new List<Employee>()
+            {
+                new Employee(){ Id=1, Name="gaofeng",Emails=new List<string>(){"a1@163.com","a2@163.com","a3@163.com"} },
+                new Employee(){ Id=1, Name="zhangsan",Emails=new List<string>(){ "b1@163.com", "b2@163.com", "b3@163.com" } }
+            };
+
+            var lookup = persons.ToLookup(q => q.Name, e => e.Emails,EqualityComparer<string>.Default);
+            var group1_Emails = lookup["gaofeng"].FirstOrDefault();
+            var group1_Emails_first = group1_Emails.FirstOrDefault();
+
+            Assert.Equal("a1@163.com", group1_Emails_first);
+        }
+        #endregion
+
+        #region private
+
+        private DataTable GetDataTable()
+        {
+
+            DataTable dt = new DataTable();
+            DataColumn col_id = new DataColumn("Id");
+            col_id.AllowDBNull = false;
+            col_id.AutoIncrementSeed = 1;
+            col_id.AutoIncrement = true;
+            col_id.AutoIncrementStep = 1;
+            col_id.DataType = typeof(int);
+
+            DataColumn col_name = new DataColumn("Name");
+            col_name.AllowDBNull = true;
+            col_name.AutoIncrement = false;
+            col_name.DataType = typeof(string);
+            col_name.DefaultValue = string.Empty;
+
+            DataColumn col_age = new DataColumn("Age");
+            col_age.AllowDBNull = false;
+            col_age.AutoIncrement = false;
+            col_age.DataType = typeof(int);
+            col_age.DefaultValue = 20;
 
             dt.Columns.Add(col_id);
             dt.Columns.Add(col_name);
             dt.Columns.Add(col_age);
 
             var row_one = dt.NewRow();
-            row_one[1]="王高峰";
+            row_one[1] = "王高峰";
-            row_one[2]=21;
+            row_one[2] = 21;
 
             var row_2 = dt.NewRow();
-            row_2[1]="王向前";
+            row_2[1] = "王向前";
-            row_2[2]=32;
+            row_2[2] = 32;
 
             dt.Rows.Add(row_one);
             dt.Rows.Add(row_2);
@@ -209,6 +397,6 @@ namespace LinqStudy.Test.LinqToObject
 
             return arrStudent;
         }
-
+        #endregion
     }
 }