Difference between is and as in C #

1. Is checks whether the object is compatible with the given type

@ 1 check whether the object is an instance or inherited from the parent class

If (students is person)

{

... // Code

}

@ 2 is operator only consider packing, unpacking, and reference conversion;

@ 3 anonymous methods are not allowed on the left side of the is Operator (except for lambda expressions)

Ex:

View code

1 int A = 10; 2 object OBJ = A; 3 if (obj is int) 4 {5 console. writeline ("boxing... "); 6} 7 A = 20; 8 console. writeline ("A = {0}", a); 9 console. writeline ("OBJ = {0}", OBJ); 10 11 12 // output result: 13 boxing... 14 A = 2015 OBJ = 10

 

II. The as operator is used to convert compatible types

@ 1 The as operator is similar to type conversion. The difference is that if the as operator fails to be converted, no error is returned, but a null value is returned;

@ 2 The as operator only performs conversion by referencing, earning, and packing. The as operator cannot perform conversion by definition;

View code

 1             object[] obj=new object[5]; 2             obj[0] = new MyClass(); 3             obj[1] = "hello"; 4             obj[2] = 123; 5             obj[3] = null; 6             obj[4] = 'a'; 7             for (int i = 0; i < obj.Length; i++) 8             { 9                 string s = obj[i] as string;10                 if(s!=null)11                 {12                     Console.WriteLine(s);13                 }14                 else15                 {16                     Console.WriteLine("not string ...");17                 }18             }