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我有一個WPF應用程序，其中PageItems是模型對象。如何模擬多重繼承並使用反射來優化此代碼？
我的主ViewModel的ObservableCollection爲PageItemViewModels，每個人都從其匹配的PageItem模型對象構建自己。
每個PageItemViewModel從抽象類BaseViewModel繼承，以獲得INotifyPropertyChanged的功能。
每個PageItemViewModel也實現了IPageItemViewModel，以確保它具有所需的性能。
我最終將有大約50頁，所以我想消除任何不必要的代碼：
- 解決（見下文）：有沒有辦法，我可以得到PageItemViewModel類繼承IDCODE和標題所以我不必在每個班級實施它們？我不能將它們放在BaseViewModel中，因爲其他ViewModel繼承了它，它們不需要這些屬性，我不能將它們放在IPageItemViewModel中，因爲它只是一個接口。我明白我需要多重繼承這其中C＃不支持
- 解決（見下文）：有沒有方法可以讓我擺脫開關語句，例如莫名其妙地用反射代替？
下面是一個獨立的控制檯應用程序這表明我的代碼在我WPF應用：
using System.Collections.Generic;
namespace TestInstantiate838
{
public class Program
{
static void Main(string[] args)
{
List<PageItem> pageItems = PageItems.GetAll();
List<ViewModelBase> pageItemViewModels = new List<ViewModelBase>();
foreach (PageItem pageItem in pageItems)
{
switch (pageItem.IdCode)
{
case "manageCustomers":
pageItemViewModels.Add(new PageItemManageCustomersViewModel(pageItem));
break;
case "manageEmployees":
pageItemViewModels.Add(new PageItemManageEmployeesViewModel(pageItem));
break;
default:
break;
}
}
}
}
public class PageItemManageCustomersViewModel : ViewModelBase, IPageItemViewModel
{
public string IdCode { get; set; }
public string Title { get; set; }
public PageItemManageCustomersViewModel(PageItem pageItem)
{
}
}
public class PageItemManageEmployeesViewModel : ViewModelBase, IPageItemViewModel
{
public string IdCode { get; set; }
public string Title { get; set; }
public PageItemManageEmployeesViewModel(PageItem pageItem)
{
}
}
public interface IPageItemViewModel
{
//these are the properties which every PageItemViewModel needs
string IdCode { get; set; }
string Title { get; set; }
}
public abstract class ViewModelBase
{
protected void OnPropertyChanged(string propertyName)
{
//this is the INotifyPropertyChanged method which all ViewModels need
}
}
public class PageItem
{
public string IdCode { get; set; }
public string Title { get; set; }
}
public class PageItems
{
public static List<PageItem> GetAll()
{
List<PageItem> pageItems = new List<PageItem>();
pageItems.Add(new PageItem { IdCode = "manageCustomers", Title = "ManageCustomers"});
pageItems.Add(new PageItem { IdCode = "manageEmployees", Title = "ManageEmployees"});
return pageItems;
}
}
}
重構：接口改爲抽象類
using System;
using System.Collections.Generic;
namespace TestInstantiate838
{
public class Program
{
static void Main(string[] args)
{
List<PageItem> pageItems = PageItems.GetAll();
List<ViewModelPageItemBase> pageItemViewModels = new List<ViewModelPageItemBase>();
foreach (PageItem pageItem in pageItems)
{
switch (pageItem.IdCode)
{
case "manageCustomers":
pageItemViewModels.Add(new PageItemManageCustomersViewModel(pageItem));
break;
case "manageEmployees":
pageItemViewModels.Add(new PageItemManageEmployeesViewModel(pageItem));
break;
default:
break;
}
}
foreach (ViewModelPageItemBase pageItemViewModel in pageItemViewModels)
{
System.Console.WriteLine("{0}:{1}", pageItemViewModel.IdCode, pageItemViewModel.Title);
}
Console.ReadLine();
}
}
public class PageItemManageCustomersViewModel : ViewModelPageItemBase
{
public PageItemManageCustomersViewModel(PageItem pageItem)
{
IdCode = pageItem.IdCode;
Title = pageItem.Title;
}
}
public class PageItemManageEmployeesViewModel : ViewModelPageItemBase
{
public PageItemManageEmployeesViewModel(PageItem pageItem)
{
IdCode = pageItem.IdCode;
Title = pageItem.Title;
}
}
public abstract class ViewModelPageItemBase : ViewModelBase
{
//these are the properties which every PageItemViewModel needs
public string IdCode { get; set; }
public string Title { get; set; }
}
public abstract class ViewModelBase
{
protected void OnPropertyChanged(string propertyName)
{
//this is the INotifyPropertyChanged method which all ViewModels need
}
}
public class PageItem
{
public string IdCode { get; set; }
public string Title { get; set; }
}
public class PageItems
{
public static List<PageItem> GetAll()
{
List<PageItem> pageItems = new List<PageItem>();
pageItems.Add(new PageItem { IdCode = "manageCustomers", Title = "ManageCustomers"});
pageItems.Add(new PageItem { IdCode = "manageEmployees", Title = "ManageEmployees"});
return pageItems;
}
}
}
回答消除開關聲明：
感謝戳刺：
string assemblyName = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name;
string viewModelName = assemblyName + ".ViewModels.PageItem" + StringHelpers.ForcePascalNotation(pageItem.IdCode) + "ViewModel";
var type = Type.GetType(viewModelName);
var viewModel = Activator.CreateInstance(type, pageItem) as ViewModelBase;
AllPageViewModels.Add(viewModel);
這只是我尋找的實用方法，我不得不嘮叨一下我上面發佈的代碼，謝謝！ – 2009-06-22 16:32:46