Interface (Interface)

Interface

Declare the interface

The interface uses the interface keyword declaration, which is similar to the class declaration. T he interface declaration is public by default. Here is an example of an interface declaration:

public interface ITransactions
{
   // 接口成员
   void showTransaction();
   double getAmount();
}

The following example demonstrates the implementation of the interface above:

using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace InterfaceApplication
{

   public interface ITransactions
   {
      // 接口成员
      void showTransaction();
      double getAmount();
   }
   public class Transaction : ITransactions
   {
      private string tCode;
      private string date;
      private double amount;
      public Transaction()
      {
         tCode = " ";
         date = " ";
         amount = 0.0;
      }
      public Transaction(string c, string d, double a)
      {
         tCode = c;
         date = d;
         amount = a;
      }
      public double getAmount()
      {
         return amount;
      }
      public void showTransaction()
      {
         Console.WriteLine("Transaction: {0}", tCode);
         Console.WriteLine("Date: {0}", date);
         Console.WriteLine("Amount: {0}", getAmount());

      }

   }
   class Tester
   {
      static void Main(string[] args)
      {
         Transaction t1 = new Transaction("001", "8/10/2012", 78900.00);
         Transaction t2 = new Transaction("002", "9/10/2012", 451900.00);
         t1.showTransaction();
         t2.showTransaction();
         Console.ReadKey();
      }
   }
}

When the above code is compiled and executed, it produces the following results:

Transaction: 001
Date: 8/10/2012
Amount: 78900
Transaction: 002
Date: 9/10/2012
Amount: 451900

Precautions for interface use:

1. Interface methods cannot be decorated with public abstracts, etc. There can be no field variables in the interface, constructors.
2. Properties (methods with get and set) can be defined within the interface. S uch as string color s get; s et ; This kind of.
3. When implementing an interface, it must be in the same format as the interface.
4. All methods of the interface must be implemented.