Use of C # as and is

2. Type conversions
   
   • Any type can be converted to its base class type, complete with implicit conversion;
   • When any type is converted to its derived type, the conversion must be displayed. such as: (type name) object name;
   • The exact type of any object can be obtained using GetType;
   • Primitive types can use the Convert class to implement type conversions;
   • Other than string types have the parse method, which is used to convert the string type to the corresponding base type;
   • Conversion of value types and reference types is called boxing (boxing) or unboxing (unboxing);
3. as/is Example
   
   • is conversion rule:
   • Check the compatibility of object types and return the result true (false);
   • Does not throw an exception;
   • If the object is null, just returns false;
     Example:
     

     1 Objecto ="ABC"; 2 if(O is string)//perform the first type compatibility check3 {  4     strings = (string) O;//perform a second type compatibility check and convert5MessageBox.Show ("The conversion was successful! "); 6 }  7 Else  8 {  9MessageBox.Show ("conversion failed! "); Ten}

   • As conversion rules:
   • Checks the compatibility of the object type and returns the result of the conversion, or null if incompatible;
   • Does not throw an exception;
   • If the result is judged to be null, then forcing the type conversion throws a NullReferenceException exception; Example:

     1 Objecto ="ABC"; 2 strings = O as string;//performs the first type compatibility check and returns the result3 if(s! =NULL)   4MessageBox.Show ("The conversion was successful! "); 5 Else  6MessageBox.Show ("conversion failed! ");

     As is less performing a compatibility check than is, performance can be a little bit higher.

Use of C # as and is