c#6 新增的特性

昨日更新了VS2015,今日学习了C#6 新增的几个特性，特记录下来，增强记忆。

1.自动的属性初始化器（Auto Property Initialzier）

    public class AutoProperBeforCsharp6
    {
        private string _property = string.Empty;
        public string Property
        {
            get; set;
        }
        public AutoProperBeforCsharp6(string value)
        {
            Property = value;
        }
    }

    public class AutoPropertyInCsharp6
    {
        public string Property { get; } = string.Empty;
    }

2.主构造器

    public class PrimaryConstructorBeforeCsharp6
    {
        public string Name { get; set; }
        public string Value { get; set; }
        public PrimaryConstructorBeforeCsharp6(string name, string value)
        {
            Name = name;
            Value = value;
        }
    }

    public class PrimaryConstructorInCsharp6(string name,string value)
    {
        public string Name { get; set; } = name;
        public string Value { get; set; } = value;
    }

3.字典初始化器

    public class DictionaryInitialzierBeforeCsharp6
    {
        public Dictionary<string, string> dic = new Dictionary<string, string>()
        {
            { "name","zhangsan"},
            { "age","18"}
        };
    }

    public class DictionaryInitialzierInCsharp6
    {
        public Dictionary<string, string> dic = new Dictionary<string, string>()
        {
            ["name"] = "zhangsan",
            ["age"] = "18"
        };
    }

4.异常过滤器

//Before C# 6 
 
//示例 1
try
{
    //Some code
}
catch (Exception ex) 
{
    if(ex.InnerException != null)
    {
        //Do work;
    }
}



//In C# 6
try
{
    //Some code
}
catch (Exception ex) if (ex.InnerException == null)
{
    //Do work
 
}
 

5. 用于检查Null值得条件运算符

//Before C# 6
var userRank = "No Rank";
if(UserID != null)
{
    userRank = Rank;
}
 
//or
 
var userRank = UserID != null ? Rank : "No Rank"



//In C# 6
var userRank = UserID?.Rank ?? "No Rank";

6.用Lamda作为函数体 Expression bodies on Method-like members

    public class UserBeforeCsharp6
    {
        public int Id { get; }
        public String Name { get; set; }
        public override string ToString()
        {
            return $"Id:{Id} Name:{Name}";
        }
    }


    //After
    public class UserInCsharp6
    {
        public int Id { get; }
        public String Name { get; set; }
        public override string ToString() => $"Id:{Id} Name:{Name}";
    }

7. 无参数的结构体构造函数 Parameterless Constructors in Struct