Maximizing.ASP.dot.NET.Real.World.ObjectOriented.Development [Electronic resources] نسخه متنی

Choosing Our Properties

Let's start writing our class by declaring it and creating the necessary references that we'll need in Listing 5.2. We'll also set up the properties and corresponding private variables.

Listing 5.2. The start of our data class

C#

using System;
using System.Data;
using System.Data.SqlClient;
using System.Web;
namespace UberAspNet
{
public class Customer
{
private int _CustomerID;
public int CustomerID
{
get {return _CustomerID;}
}
private string _LastName;
public string LastName
{
get {return _LastName;}
set {_LastName = value;}
}
private string _FirstName;
public string FirstName
{
get {return _FirstName;}
set {_FirstName = value;}
}
private string _Address;
public string Address
{
get {return _Address;}
set {_Address = value;}
}
private string _City;
public string City
{
get {return _City;}
set {_City = value;}
}
private string _State;
public string State
{
get {return State;}
set {_State = value;}
}
private string _Zip;
public string Zip
{
get {return _Zip;}
set {_Zip = value;}
}
private string _Phone;
public string Phone
{
get {return _Phone;}
set {_Phone = value;}
}
private DateTime _SignUpDate;
public DateTime SignUpDate
{
get {return _SignUpDate;}
set {_SignUpDate = value;}
}
}
}

VB.NET

Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web
Namespace UberAspNet
Public Class Customer
Private _CustomerID As Integer
Public ReadOnly Property CustomerID() As Integer
Get
Return _CustomerID
End Get
End Property 
Private _LastName As String
Public Property LastName() As String
Get
Return _LastName
End Get
Set
_LastName = value
End Set
End Property 
Private _FirstName As String
Public Property FirstName() As String
Get
Return _FirstName
End Get
Set
_FirstName = value
End Set
End Property 
Private _Address As String
Public Property Address() As String
Get
Return _Address
End Get
Set
_Address = value
End Set
End Property 
Private _City As String
Public Property City() As String
Get
Return _City
End Get
Set
_City = value
End Set
End Property 
Private _State As String
Public Property State() As String
Get
Return State
End Get
Set
_State = value
End Set
End Property 
Private _Zip As String
Public Property Zip() As String
Get
Return _Zip
End Get
Set
_Zip = value
End Set
End Property 
Private _Phone As String
Public Property Phone() As String
Get
Return _Phone
End Get
Set
_Phone = value
End Set
End Property 
Private _SignUpDate As DateTime
Public Property SignUpDate() As DateTime
Get
Return _SignUpDate
End Get
Set
_SignUpDate = value
End Set
End Property
End Class
End Namespace

The code is fairly straightforward. We've created a property to correspond to each of the columns in our database table, matching the data types. We've also created a private variable for each column for internal use in our class. The only unusual thing here is that we've made the CustomerID property read-only. That's because our database table is designed to make this a primary key and an identity field, meaning that SQL Server will number the column automatically when we add new rows. For that reason, we don't want the class to have the ability to alter this property. This read-only strategy also protects other developers (or yourself if you can't remember every detail about what you've written) from doing something that could break the program.

You could declare default values for each private variable, but we're going to defer those assignments to our constructors. We might want to assign different default values depending on the overload of the constructor called.