Security transformations for data types in C # (Is,as)

Safe conversion of data types in the original C # (Is,as)

The following code, which cannot be boxed, has an error forcing the type conversion because it is not possible to convert it to an int type, since C is the class type. Although the compiler can compile, runtime throws a InvalidCastException exception at run time.

    Circle C = New Circle (8);      Object o = C;   This clause is correct, but will not be boxed, because boxing is from the stack to the heap, the value type is required, and C is the reference type      int i = (int) o;//compile succeeded                       //compiler compile pass, but runtime runtime throws a Invalidcastexc Eption  

is and as are operators that C # provides for performing type casts in a safe manner, using the following usage.

The is operator verifies that the object's type is not what it wants.

    Wrappedint WI = new Wrappedint ();      Object o = wi;      If (O is Wrappedint)      {          Wrappedint temp = (wrappedint) o;    Transition is secure, O has been determined to be a wrappedint      }  

The as operator takes an object and a type as its left and right operands.

Runtime attempts to convert the object to the specified type, and if the conversion succeeds , returns The result of the successful conversion to temp, and returns null to Temp if the conversion fails .

    Wrappedint WI = new Wrappedint ();      Object o = wi;      Wrappedint temp = o as wrappedint;    The transition is secure, O is determined to be a wrappedint      if (temp! = null)      {          //Only the conversion succeeds, the code here can be executed      }  

Security transformations for data types in C # (Is,as)