Detailed explanation of C# interface calling method examples in derived classes and external classes

This article mainly introduces the calling methods of the C#interface in derived classes and external classes. It analyzes the definition and specific usage of the C# interface in combination with examples. What is needed Friends can refer to

The examples in this article describe the calling methods of C# interfaces in derived classes and external classes. Share it with everyone for your reference, the details are as follows:

The interface of C# is created through the interface keyword, and the interface can contain member variables such as properties and methods. Derived classes of interfaces can implement methods in the interface. A class can inherit multiple interfaces to implement the methods in these interfaces, and an interface can also derive multiple classes. The methods in the interface can be implemented by one or more of these classes. Methods in the interface can be directly called in derived classes of the interface.

Example of calling in a derived class:

//接口
public interface IPersonalService
{
   //接口中的方法
   PersonalDTO QueryByUid(int uId);
}
//接口派生类
public class PersonalService : IPersonalService
{
    //派生类中实现接口方法--隐式实现
    public PersonalDTO QueryByUid(int uId)
    {
      return _dal.QueryByUid(uId);
    }
    //派生类中调用接口方法
    public void GetInfo(int userId)
    {
      //调用方式一
      IPersonalService p = new PersonalService();
      PersonalDTO dto = p.QueryByUid(userId);
      //调用方式二
      PersonalService p2 = new PersonalService();
      IPersonalService p3 = (IPersonalService)p2;
      PersonalDTO dto = p3.QueryByUid(userId);
    }
}

When calling a method of an interface in an external class, firstreference thenamespacewhere the interface is locatedand then The steps are the same as calling in the derived class of the interface.

You can also call the interface by declaring an attribute of the interface type after referencing the namespace where the interface is located in the external class, as follows.

public IPersonalService pService{get;set;}
public void getInfo()
{
    pService.getInfo();
}

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