3/31/2023 0 Comments Type to learn 3 online free![]() ![]() 8.2.6 Interface typesĪn interface defines a contract. The keyword string is simply an alias for the predefined class System.String. Values of the string type can be written as string literals ( §6.4.5.6). Instances of the string class represent Unicode character strings. The string type is a sealed class type that inherits directly from object. The dynamic type is further described in §8.7, and dynamic binding in §11.3.1. Instead, an exception will be thrown when resolution of the operation fails at run-time. Thus, if the operation cannot legitimately be applied to the referenced object, no error is given during compilation. When operations are applied to expressions of type dynamic, their resolution is deferred until the program is run. ![]() The dynamic type, like object, can reference any object. The keyword object is simply an alias for the predefined class System.Object. Every type in C# directly or indirectly derives from the object class type. The object class type is the ultimate base class of all other types. The ultimate base class of all other types. Instances of class types are created using object_creation_expressions ( §11.7.15.2).Ĭertain predefined class types have special meaning in the C# language, as described in the table below. Class types support inheritance, a mechanism whereby derived classes can extend and specialize base classes. 8.2.2 Class typesĪ class type defines a data structure that contains data members (constants and fields), function members (methods, properties, events, indexers, operators, instance constructors, finalizers, and static constructors), and nested types. The special value null is compatible with all reference types and indicates the absence of an instance. Pointer_type is available only in unsafe code ( §22.3).Ī reference type value is a reference to an instance of the type, the latter known as an object. 8.2 Reference types 8.2.1 GeneralĪ reference type is a class type, an interface type, an array type, a delegate type, or the dynamic type. Values of value types are treated as objects by performing boxing and unboxing operations ( §8.3.12).įor convenience, throughout this specification, some library type names are written without using their full name qualification. Values of reference types are treated as objects simply by viewing the values as type object. Every type in C# directly or indirectly derives from the object class type, and object is the ultimate base class of all types. end noteĬ#’s type system is unified such that a value of any type can be treated as an object. In this case, the ref or out variable is effectively an alias for another variable and not a distinct variable. Note: When a variable is a ref or out parameter, it does not have its own storage but references the storage of another variable. With value types, the variables each have their own copy of the data, and it is not possible for operations on one to affect the other. With reference types, it is possible for two variables to reference the same object, and thus possible for operations on one variable to affect the object referenced by the other variable. Value types differ from reference types in that variables of the value types directly contain their data, whereas variables of the reference types store references to their data, the latter being known as objects. Pointer_type ( §22.3) is available only in unsafe code ( §22). Type parameters can designate both value types and reference types. Both value types and reference types may be generic types, which take one or more type parameters. The types of the C# language are divided into two main categories: reference types and value types. ![]()
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