C#6.0新特性

public class SharpSixNewInfo
    {
        public static void Show() {
            //条件运算
            {
                Student stu = null;
                //获取属性对象为空返回null
                string lastName = stu?.LastName;
                Console.WriteLine(lastName);
                //对象为空属性也为空返回其他字符串
                string result = stu?.FirstName ?? "1";
                Console.WriteLine(result);
            }
            //异常捕获，过滤异常符合进入
            {
                //StaticClass.ExceptionShow();
            }
            //事件回调
            {
                NotifyPropertyChanged notifyPropertyChanged = new NotifyPropertyChanged();
                notifyPropertyChanged.PropertyChanged += (object o, PropertyChangedEventArgs b) =>
                {
                    Console.WriteLine(o);
                };
                notifyPropertyChanged.LastName = "test";

            }
        }
        
    }
    /// <summary>
    /// 赋值后调用事件，发布订阅模式
    /// </summary>
    public class NotifyPropertyChanged : INotifyPropertyChanged
    {
        public string LastName {
            get { return lastName; }

            set {
                if (value != lastName) {
                    lastName = value;
                    PropertyChanged?.Invoke(this, 
                        new PropertyChangedEventArgs(nameof(LastName)));
                }
            }
        }
        private string lastName;
        public event PropertyChangedEventHandler PropertyChanged;
    }

    /// <summary>
    /// 异常捕获
    /// </summary>
    public class StaticClass {
        public static void ExceptionShow() {
            try
            {
                throw new Exception("测试");
            }
            catch (Exception ex) when(ex.Message.Contains("测试"))    //过滤异常信息，条件符合进入异常
            {

                throw;
            }
        }
    }
    public class Student { 
        public int? Id { get; set; }

        public string FirstName { get; set; }

        public string LastName { get; set; }
    }