using System;
using System.Data;
using System.Data.OleDb;
namespace DoFactory.GangOfFour.Template.RealWorld
{
// MainApp test application
class MainApp
{
static void Main()
{
DataAccessObject dao;
dao = new Categories();
dao.Run();
dao =
new Products();
dao.Run();
// Wait for user
Console.Read();
}
}
// "AbstractClass"
abstract class DataAccessObject
{
protected string connectionString;
protected DataSet dataSet;
public virtual void Connect()
{
// Make sure mdb is on c:\
connectionString =
"provider=Microsoft.JET.OLEDB.4.0; " +
"data source=c:\\nwind.mdb";
}
public abstract void Select();
public abstract void Process();
public virtual void Disconnect()
{
connectionString = "";
}
// The "Template Method"
public void Run()
{
Connect();
Select();
Process();
Disconnect();
}
}
// "ConcreteClass"
class Categories : DataAccessObject
{
public override void Select()
{
string sql = "select CategoryName from Categories";
OleDbDataAdapter dataAdapter = new OleDbDataAdapter(
sql, connectionString);
dataSet =
new DataSet();
dataAdapter.Fill(dataSet, "Categories");
}
public override void Process()
{
Console.WriteLine("Categories ---- ");
DataTable dataTable = dataSet.Tables["Categories"];
foreach (DataRow row in dataTable.Rows)
{
Console.WriteLine(row["CategoryName"]);
}
Console.WriteLine();
}
}
class Products : DataAccessObject
{
public override void Select()
{
string sql = "select ProductName from Products";
OleDbDataAdapter dataAdapter = new OleDbDataAdapter(
sql, connectionString);
dataSet =
new DataSet();
dataAdapter.Fill(dataSet, "Products");
}
public override void Process()
{
Console.WriteLine("Products ---- ");
DataTable dataTable = dataSet.Tables["Products"];
foreach (DataRow row in dataTable.Rows)
{
Console.WriteLine(row["ProductName"]);
}
Console.WriteLine();
}
}
}
