c# - 无法使用我从 MSDN 复制的代码覆盖继承的成员 SelectTemplate...

Question

我有一个覆盖问题。我知道您不能覆盖继承的成员，除非它们被标记为虚拟、抽象或覆盖，但是...

我有this code来自 msdn:

using System.Windows;
using System.Windows.Controls;

namespace SDKSample
{
    public class TaskListDataTemplateSelector : DataTemplateSelector
    {
        public override DataTemplate
            SelectTemplate(object item, DependencyObject container)
        {
            FrameworkElement element = container as FrameworkElement;

            if (element != null && item != null && item is Task)
            {
                Task taskitem = item as Task;

                if (taskitem.Priority == 1)
                    return
                        element.FindResource("importantTaskTemplate") as DataTemplate;
                else 
                    return
                        element.FindResource("myTaskTemplate") as DataTemplate;
            }

            return null;
        }
    }
}

然后我添加了这段代码:

public class PostTemplateSelector : DataTemplateSelector
{
    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        ListViewItem lvi = item as ListViewItem;

        AppNetClient.PostClass key = lvi.DataContext as AppNetClient.PostClass;

        if (key.postTemplate == "Post")
        {
            return lvi.FindName("PostDataTemplate") as DataTemplate;
        }
        else
        {
            return lvi.FindName("SelectedPostDataTemplate") as DataTemplate;
        }
    }
}

我得到这个错误:

Error   3   'oneSocialLife.MainPage.PostTemplateSelector.SelectTemplate(object, Windows.UI.Xaml.DependencyObject)': cannot override inherited member 'Windows.UI.Xaml.Controls.DataTemplateSelector.SelectTemplate(object, Windows.UI.Xaml.DependencyObject)' because it is not marked virtual, abstract, or override   C:\Users\kcone\documents\visual studio 2012\Projects\HttpClientApp\HttpClientApp\MainPage.xaml.cs   339 42  oneSocialLife

我花了几个小时寻找原因，但无法弄清楚。有什么想法吗？

Answer 1

您引用的示例适用于 WPF ( System.Windows.Controls.DataTemplateSelector )。

在 Windows 应用商店应用中，您使用的是 Windows.UI.Xaml.Controls.DataTemplateSelector有不同的语义，SelectTemplate确实不可覆盖，但是 SelectTemplateCore是。