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）

 1     public class AutoProperBeforCsharp6
 2     {
 3         private string _property = string.Empty;
 4         public string Property
 5         {
 6             get; set;
 7         }
 8         public AutoProperBeforCsharp6(string value)
 9         {
10             Property = value;
11         }
12     }
13 
14     public class AutoPropertyInCsharp6
15     {
16         public string Property { get; } = string.Empty;
17     }

2.主构造器

 1     public class PrimaryConstructorBeforeCsharp6
 2     {
 3         public string Name { get; set; }
 4         public string Value { get; set; }
 5         public PrimaryConstructorBeforeCsharp6(string name, string value)
 6         {
 7             Name = name;
 8             Value = value;
 9         }
10     }
11 
12     public class PrimaryConstructorInCsharp6(string name,string value)
13     {
14         public string Name { get; set; } = name;
15         public string Value { get; set; } = value;
16     }

3.字典初始化器

 1     public class DictionaryInitialzierBeforeCsharp6
 2     {
 3         public Dictionary<string, string> dic = new Dictionary<string, string>()
 4         {
 5             { "name","zhangsan"},
 6             { "age","18"}
 7         };
 8     }
 9 
10     public class DictionaryInitialzierInCsharp6
11     {
12         public Dictionary<string, string> dic = new Dictionary<string, string>()
13         {
14             ["name"] = "zhangsan",
15             ["age"] = "18"
16         };
17     }

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

 1 //Before C# 6
 2 var userRank = "No Rank";
 3 if(UserID != null)
 4 {
 5     userRank = Rank;
 6 }
 7  
 8 //or
 9  
10 var userRank = UserID != null ? Rank : "No Rank"
11 
12 
13 
14 //In C# 6
15 var userRank = UserID?.Rank ?? "No Rank";

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

 1     public class UserBeforeCsharp6
 2     {
 3         public int Id { get; }
 4         public String Name { get; set; }
 5         public override string ToString()
 6         {
 7             return $"Id:{Id} Name:{Name}";
 8         }
 9     }
10 
11 
12     //After
13     public class UserInCsharp6
14     {
15         public int Id { get; }
16         public String Name { get; set; }
17         public override string ToString() => $"Id:{Id} Name:{Name}";
18     }

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