Filter
Top Products
Chapter 4: Learning Just Enough C# and VB.NET: Intermediate Syntax 97
Creating an Interface
To create an interface, right-click the project in Solution Explorer, select Add | New Item,
select Code under the language branch in Installed Templates, and select the Interface item.
Name the Interface IAccount and click Add. By standard convention, you will always
name any interface class you create with a name that starts with an uppercase letter I. You’ll
see the interface in Listing 4-2 added to your project:
Listing 4-2 An interface
C#:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace FirstProgram
{
public interface IAccount
{
void Credit(decimal amount);
void Debit(decimal amount);
decimal CurrentBalance { get; set; }
}
}
VB:
Public Interface IAccount
Sub Credit(ByVal amount As Decimal)
Sub Debit(ByVal amount As Decimal)
Property CurrentBalance As Decimal
End Interface
After you’ve added the interface, you’ll need to make modifications to make the code
match Listing 4-2. Notice that the IAccount members don’t have an implementation and
so appear incomplete because they have no lines of code. Also, each member doesn’t have
a public modifier, because interface members are implicitly public. The following sections
show you how to build the classes that implement the IAccount interface; there, you
should begin to see the benefit that an interface can bring.