教你在c#中实现3层架构

    using System.Data;

    namespace _3tierarchitecture

    {

    /// <SUMMARY>

    /// Summary description for BOCustomer.

    /// </SUMMARY>

    public class BOCustomer

    {

    //Customer properties

    private String fName;

    private String lName;

    private String cusId;

    private String address;

    private String tel;

    private DACustomer cusData;

    public BOCustomer()

    {

    //An instance of the Data access layer!

    cusData = new DACustomer();

    }

    /// <SUMMARY>

    /// Property FirstName (String)

    /// </SUMMARY>

    public String FName

    {

    get

    {

    return this.fName;

    }

    set

    {

    try

    {

    this.fName = value;

    if (this.fName == "")

    {

    throw new Exception(

    "Please provide first name ...");

    }

    }

    catch(Exception e)

    {

    throw new Exception(e.Message.ToString());

    }

    }

    }

    /// <SUMMARY>

    /// Property LastName (String)

    /// </SUMMARY>

    public String LName

    {

    get

    {

    return this.lName;

    }

    set

    {

    //could be more checkings here eg revmove ' chars

    //change to proper case

    //blah blah

    this.lName = value;

    if (this.LName == "")

    {

    throw new Exception("Please provide name ...");

    }

    }

    }

    /// <SUMMARY>

    /// Property Customer ID (String)

    /// </SUMMARY>

    public String cusID

    {

    get

    {

    return this.cusId;

    }

    set

    {

    this.cusId = value;

    if (this.cusID == "")

    {

    throw new Exception("Please provide ID ...");

    }

    }

    }

    /// <SUMMARY>

    /// Property Address (String)

    /// </SUMMARY>

    public String Address

    {

    get

    {

    return this.address;

    }

    set

    {

    this.address = value;

    if (this.Address == "")

    {

    throw new Exception("Please provide address ...");

    }

    }

    }

    /// <SUMMARY>

    /// Property Telephone (String)

    /// </SUMMARY>

    public String Tel

    {

    get

    {

    return this.tel;

    }

    set

    {

    this.tel = value;

    if (this.Tel == "")

    {

    throw new Exception("Please provide Tel ...");

    }

    }

    }

    /// <SUMMARY>

    /// Function Add new customer. Calls

    /// the function in Data layer.

    /// </SUMMARY>

    public void Add()

    {

    cusData.Add(this);

    }

    /// <SUMMARY>

    /// Function Update customer details.

    /// Calls the function in Data layer.

    /// </SUMMARY>

    public void Update()

    {

    cusData.Update(this);

    }

    /// <SUMMARY>

    /// Function Find customer. Calls the

    /// function in Data layer.

    /// It returns the details of the customer using

    /// customer ID via a Dataset to GUI tier.

    /// </SUMMARY>

    public DataSet Find(String str)

    {

    if (str == "")

    throw new Exception("Please provide ID to search");

    DataSet data = null;

    data = cusData.Find(str);

    return data;

    }

    }

    }