{"id":388,"date":"2022-01-06T09:21:09","date_gmt":"2022-01-06T02:21:09","guid":{"rendered":"https:\/\/csharptutorial.net\/?page_id=388"},"modified":"2022-06-03T14:57:52","modified_gmt":"2022-06-03T07:57:52","slug":"csharp-new-modifier","status":"publish","type":"page","link":"https:\/\/www.csharptutorial.net\/csharp-tutorial\/csharp-new-modifier\/","title":{"rendered":"C# new Modifier"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about how to use the C# new modifier for the members of a subclass to explicitly hide a member with the same name from the base class.<\/p>\n\n\n\n

Introduction to the C# new modifier<\/h2>\n\n\n\n

In inheritance<\/a>, if a member of a subclass has the same name as the member of a base class, the C# compiler will issue a warning. For example:<\/p>\n\n\n

class<\/span> Person<\/span>\n{\n    public<\/span> string<\/span> Name { get<\/span>; set<\/span>; }\n\n    public<\/span> string<\/span> Introduce<\/span>(<\/span>)<\/span> => $\"Hi, I'm {Name}<\/span>.\"<\/span>;\n}\n\nclass<\/span> Employee<\/span> : Person<\/span>\n{\n    public<\/span> string<\/span> JobTitle { get<\/span>; set<\/span>; }\n\n    public<\/span> string<\/span> Introduce<\/span>(<\/span>)<\/span> => $\"Hi, I'm {Name}<\/span>. I'm a {JobTitle}<\/span>.\"<\/span>;\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example:<\/p>\n\n\n\n
  • The Person<\/code> is the base class and the Employee<\/code> is a subclass that inherits from the Person<\/code> class.<\/li>
  • Both Person<\/code> and Employee<\/code> classes have the same method Introduce()<\/code> that returns a string.<\/li><\/ul>\n\n\n\n
    C# compiler issues the following warning:<\/p>\n\n\n
    'Employee.Introduce()' hides inherited member 'Person.Introduce()'. Use the new keyword if hiding was intended.<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
    It clearly indicates that the Introduce()<\/code> method of the Employee<\/code> class hides the Introduce()<\/code> method of the Person<\/code> class.<\/p>\n\n\n\n
    When a method in the subclass hides a member from the base class, the member in the subclass replaces the member of the base class.<\/p>\n\n\n\n
    Typically, you don’t want to hide a method of the base class. Usually, this happens by accident when you add a method to the base class with the same name as a method in the subclass. Therefore, the compiler issues the warning to help you recognize an unintended consequence earlier.<\/p>\n\n\n\n
    However, if you really want to hide a method from the base class,  you can use the new modifier for the member in the subclass. For example:<\/p>\n\n\n
    class<\/span> Person<\/span>\n{\n    public<\/span> string<\/span> Name { get<\/span>; set<\/span>; }\n\n    public<\/span> string<\/span> Introduce<\/span>(<\/span>)<\/span> => $\"Hi, I'm {Name}<\/span>.\"<\/span>;\n}\n\nclass<\/span> Employee<\/span> : Person<\/span>\n{\n    public<\/span> string<\/span> JobTitle { get<\/span>; set<\/span>; }\n\n    public<\/span> new string<\/span> Introduce<\/span>(<\/span>)<\/span> => $\"Hi, I'm {Name}<\/span>. I'm a {JobTitle}<\/span>.\"<\/span>;\n}<\/code><\/span>Code language:<\/span> C#<\/span> (<\/span>cs<\/span>)<\/span><\/small><\/pre>\n\n\n
    In this example, we add the new modifier to the Introduce()<\/code> method. The new modifier communicates our intent to the compiler and other developers that the duplicate Introduce()<\/code> method is not an accident. Also, the new modifier suppresses the compiler warning.<\/p>\n\n\n\n
    Besides methods, you can use the new modifier for other members such as fields, properties, and indexers.<\/p>\n\n\n\n
    Summary<\/h2>\n\n\n\n
    • Use the C# new modifier for the members in the subclass to hide the members of a base class.<\/li><\/ul>\n
      \n\t
      \n\t\t
      Was this tutorial helpful ?<\/div>\n\t\t
      \n\t\t\t\n\t\t\t\t\n\t\t\t\t\t<\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t Yes <\/span>\n\t\t\t<\/button>\n\n\t\t\t\n\t\t\t\t\n\t\t\t\t\t<\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t No <\/span>\n\t\t\t<\/button>\n\t\t<\/div>\n\t<\/header>\n\n\t
      \n\t\t
      \n\t\t\t
      <\/div>\n\t\t\t\n\t\t\t