How to implement an interface in C#
Syntax
The general form of a class that implements an interface is shown here:
class class-name : interface-name {
// class-body
}
To implement more than one interface, the interfaces are separated with a comma. A class can inherit a base class and also implement one or more interfaces.
The name of the base class must come first in the comma-separated list. The methods that implement an interface must be declared public.
Example
The following code defines an interface.
using System;//from w w w. j a va 2 s.com
interface Printable{
void Print();
}
class Rectangle : Printable{
int Width;
public void Print(){
Console.WriteLine("Width:"+Width);
}
}
class Test
{
static void Main()
{
Printable r = new Rectangle();
r.Print();
}
}
The output:
Example 2
Multiple Implementation: implement two interfaces
interface IFoo/*ww w.j a v a 2s .co m*/
{
void ExecuteFoo();
}
interface IBar
{
void ExecuteBar();
}
class Tester: IFoo, IBar
{
public void ExecuteFoo() {}
public void ExecuteBar() {}
}
Example 3
extend class and implement interface at the same time
public class Component
{//from w w w.j a v a 2 s .co m
public Component() {}
}
interface Printable
{
void printHeader(float factor);
void printFooter(float factor);
}
public class TextField: Component, Printable
{
public TextField(string text)
{
this.text = text;
}
// implementing Printable.printHeader()
public void printHeader(float factor)
{
}
// implementing Printable.printFooter()
public void printFooter(float factor)
{
}
private string text;
}
class MainClass
{
public static void Main()
{
TextField text = new TextField("Hello");
Printable scalable = (Printable) text;
scalable.printHeader(0.5F);
scalable.printFooter(0.5F);
}
}
The code above generates the following result.
