从基础类

Question

我继承了我需要扩展的代码并为其添加了一些功能。

我有一个基类，它存储具体对象列表“OrderA”：

private List<OrderA> _orders;

我想用通用的方法替换具体的对象实现。

现在我有：

/// <summary>
/// This is DataContract that received via a web service
/// </summary>
public class Order
{
    public string Prop1 { get; set; }
    public string Prop2 { get; set; }
}

public class OrderA : Order
{
    public string Prop3 { get; set; }
}

// Base class
public class WorksheetBase
{
    // Uses concrete OrderA object
    private List<OrderA> _orders;

    public void CreateWorksheet()
    {
        _orders = new List<OrderA>();

        for (int i = 0; i < 5; i++)
        {
            var o = new OrderA();
            o.Prop1 = string.Format("Value {0}", i);
            _orders.Add(o);
        }
    }

    public void SaveWorksheets()
    {
        if (_orders == null)
            return;

        foreach (var order in _orders)
        {
            Console.WriteLine(order.Prop1);
        }
    }
}

public class WorksheetA : WorksheetBase
{
    OrderA[] _activeOrders;

    public string Name { get; set; }
}

public class WorksheetB : WorksheetBase
{
    OrderA[] _activeOrders;

    public string Name { get; set; }
}

class Program
{
    public static Dictionary<string, WorksheetBase> dic = new Dictionary<string, WorksheetBase>();

    static void Main(string[] args)
    {
        WorksheetA fz = new WorksheetA();
        fz.Name = "Work Sheet A";
        fz.CreateWorksheet();
        dic[fz.Name] = fz;

        WorksheetB fwd = new WorksheetB();
        fwd.Name = "Work Sheet B";
        fwd.CreateWorksheet();
        dic[fwd.Name] = fwd;

        SaveWorksheets();

        Console.ReadKey();
    }

    private static void SaveWorksheets()
    {
        foreach (var item in dic)
        {
            item.Value.SaveWorksheets();
        }
    }
}

现在我需要为（WorksheetC）添加一个新功能

public class OrderC : Order
{
    public string Prop4 { get; set; }
}

public class WorksheetC : WorksheetBase
{
    OrderC[] _activeOrders;

    public string Name { get; set; }
}

我觉得实现泛型类型参数是正确的方法。

public class WorksheetBase<T>
{
    private List<T> _orders;

    public void CreateWorksheet()
    {
        _orders = new List<T>();

        for (int i = 0; i < 5; i++)
        {
            ....
        }
    }

    public void SaveWorksheets()
    {
        if (_orders == null)
            return;

        foreach (var order in _orders)
        {
            Console.WriteLine(order.Prop1);
        }
    }

}

public class WorksheetA : WorksheetBase<OrderA>
{
    OrderA[] _activeOrders;

    public string Name { get; set; }
}

但是在实例化字典时我遇到错误：

public static Dictionary<string, WorksheetBase> dic = new Dictionary<string, WorksheetBase>();

也许我说这一切都错了，但这让我烦恼。有没有想过更好的方法来处理这个？我觉得我必须要错过一些简单的东西......