在中实现层架构

/// SUMMARY

/// Function Add new customer. Calls

/// the function in Data layer.

/// /SUMMARY

public void Add()

{

d(this);

}

/// SUMMARY

/// Function Update customer details.

/// Calls the function in Data layer.

/// /SUMMARY

都是我们生活的必要工具 public void Update()

{

date(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 = nd(str);

return data;

}

}

}

数据访问层

数据层包括处理MS Access数据库的细节。所有这些细节都是透明的，不会影响到商业逻辑层。数据访问层有个指向商业逻辑层的引用BOCustomer cus。为了应用方便并且支持其他数据库。

using System;

using eDb;

using ta;

namespace _3tierarchitecture

{

/// SUMMARY

/// Summary description for DACustomer.

/// /SUMMARY

public class DACustomer

{

private OleDbConnection cnn;

//change connection string as per the

//folder you unzip the files

private const string CnnStr =

\"Provider=EDB.4.0;Data \" +

\"Source= D:\\\\Rahman_Backup\\\\Programming\\\\\" +

\"Csharp\\\\3tierarchitecture\\\\b;\";

//local variables

private String strTable=\"\";

private String strFields=\"\";

private String strValues=\"\";

private String insertStr=\"\";

//this needs to be changed based on customer

//table fields\'\' Name of the database!

private const String thisTable = \"tblCustomer\";

private const String cus_ID = \"CUS_ID\";

private const String cus_LName = \"CUS_L_NAME\";

private const String cus_FName = \"CUS_F_NAME\";

private const String cus_Tel = \"CUS_TEL\";

private const String cus_Address = \"CUS_ADDRESS\";

public DACustomer()

{

}