C#版本 与 .NET Framework 对应关系及各版本语法差异

C# 与 .NET Framework 对应关系

下表中列出 C#、.NET、VS版本对应关系

c#6.0语法

//1.只读自动属性
            {
                Student student = new Student("Richard", "Richard01");
                string fullName = student.ToString();
                string fullName1 = student.FullName;
            }
//2.using static
            {
                StaticClass.Next();
                StaticClass.NextTo();
                Next();
                NextTo();
            }
//3.Null 条件运算符
            {
                Student student = null;
                // student.FirstName; //如果student为null  未将对象引用至对象的实例
                //if (student!=null)
                //{
                //    string fullName = student.FullName;
                //}
                string fullName = student?.FullName; //得到的结果一定是要支持null

                int?  id = student?.Id; //? 只能为可空类型服务

                student = new Student("AB", "CD");
                fullName = student?.FullName;
                string testName = student?.TestName ?? "朝夕教育";
                student.TestName = "Zhaoxi教育";
                testName = student?.TestName ?? "朝夕教育";
            }
//4.字符串内插
            { 
                //string.Format();
                //stringBuilder
                //string+
                string firstName = "朝夕";
                string lastName = "教育";
                var strs = $"{{{firstName}}}-{lastName}-{firstName}-{firstName};{firstName}";
            }
//5.异常筛选器
            {
                之前都是自定义不同的Exception 继承Exception父类
                //StaticClass.ExceptionShow();
            }

//6.nameof 表达式
            {
                string clasName=  "StaticClass"; 
                string className1 = nameof(StaticClass);
                Console.WriteLine(className1);
                string className2 = nameof(SharpSixInfo);
                Console.WriteLine(className2);
                string className3 = nameof(Student);
                Console.WriteLine(className3);
//7.什么是事件？
                NotifyPropertyChanged notifyPropertyChanged = new NotifyPropertyChanged(); 
                notifyPropertyChanged.PropertyChanged += (object o, PropertyChangedEventArgs b) =>
                {
                    
                }; 
                notifyPropertyChanged.LastName = "朝夕教育";
            }
 //8.使用索引器初始化关联集合
            {
                Dictionary messages = new Dictionary
                {
                    { 404, "Page not Found"},
                    { 302, "Page moved, but left a forwarding address."},
                    { 500, "The web server can't come out to play today."}
                };
                messages.Add(405,"朝夕教育");
                messages.Remove(405, out string obj);
                Console.WriteLine(obj);

                Dictionary webErrors = new Dictionary
                {
                    [404] = "Page not Found",
                    [302] = "Page moved, but left a forwarding address.",
                    [500] = "The web server can't come out to play today."
                };
                webErrors.Add(405, "朝夕教育"); 
                webErrors.Remove(405, out string  strResult); 
            }

c#7.0语法

 #region Out变量
            {
                不需要声明
                //string input = Console.ReadLine();
                //int.TryParse(input, out int result);
                //Console.WriteLine(result);

                out 修改是可以是var类型声明
                //int.TryParse("456", out var result1);
                //Console.WriteLine(result1);

                //Console.WriteLine("****************Out*****************");

                out 变量
                //DInfo dInfo = new DInfo(123);

            }
            #endregion

#region 元组
            {
                (string Alpha, string Beta) namedLetters = ("a", "b");
                namedLetters.Alpha = "aa";
                namedLetters.Beta = "bb";
                Console.WriteLine($"{namedLetters.Alpha}, {namedLetters.Beta}");

                var alphabetStart = (Alpha: "a", Beta: "b");
                alphabetStart.Beta = "B+B";
                alphabetStart.Alpha = "A+A";
                Console.WriteLine($"{alphabetStart.Alpha}, {alphabetStart.Beta}");

                (int max, int min) = Range();
                Console.WriteLine(max);
                Console.WriteLine(min);
            }
            {
                var p = new Point(12, 13);
                Console.WriteLine(p.X);
                Console.WriteLine(p.Y);
                p.Deconstruct(out double xx, out double yy);
                Console.WriteLine(xx);
                Console.WriteLine(yy);
            }
            #endregion

#region 弃元
            {
                var (_, _, _, pop1, _, pop2) = QueryCityDataForYears("New York City", 1960, 2010);
                (string, double, int, int, int, int) result = QueryCityDataForYears("New York City", 1960, 2010);
            
            }
            #endregion

#region 模式 
            {
                int input = 123;
                int sum = 234;
                if (input is int count)
                    sum += count;
            }
            {
                //IEnumerable