如何动态绑定ContentTemplate

Question

(WPF MVVM)我正在尝试使用我自己的风格和ContentTemplate->StaticResource->DataTemplate.组合来做一个暂停/播放按钮我将DataTemplate设置为矢量图形数据。我已经准备了两个矢量图形暂停按钮和播放按钮.我的目标:如果我点击暂停按钮，ContentTemplate将被“切换”为Play- button -DataTemplate，然后按钮变成Play-Button。我知道我需要绑定按钮的单击事件或使用RelayCommand执行暂停/播放操作(在我的代码片段中，我还没有绑定Click事件)，但我不知道如何绑定ContentTemplate以获得需要的效果。提前谢谢你。

<controls:MyButton x:Name="btnPause" AutomationProperties.Name="btnPause" Style="{StaticResource MyButtonStyle}" ContentTemplate="{StaticResource dtmpPause}" />

<DataTemplate x:Name="dtmpPause">
        <Path x:Name="pathPause" Fill="White" Stretch="Uniform" Data="M314.00598,126.271 L379.52698,126.271 L379.52698,440.672 L314.00598,440.672 z M187.40198,126.271 L252.92398,126.271 L252.92398,440.672 L187.40198,440.672 z M283.45901,34.240997 C146.03,34.240997 34.229004,146.043 34.229004,283.45697 C34.229004,420.88702 146.03,532.70099 283.45901,532.70099 C420.88699,532.70099 532.70203,420.88702 532.70203,283.45697 C532.70203,146.043 420.88699,34.240997 283.45901,34.240997 z M283.45901,0 C439.772,0 566.92999,127.158 566.92999,283.45697 C566.92999,439.771 439.772,566.94299 283.45901,566.94299 C127.15799,566.94299 0,439.771 0,283.45697 C0,127.158 127.15799,0 283.45901,0 z"/>
</DataTemplate>

<DataTemplate x:Name="dtmpPlay">
    <Path x:Name="pathPlay" Fill="White" Stretch="Uniform" Data="M269.00003,121.50002 L298.00003,121.50002 L298.00003,445.50003 L269.00003,445.50003 z M283.5,41.621429 L41.620132,283.50198 L283.5,525.37958 L525.37982,283.50198 z M283.5,0 L566.99994,283.50198 L283.5,567 L0,283.50198 z"/>
</DataTemplate>

Answer 1

使用DataTemplateSelector，它允许您根据定义的条件选择您希望的DataTemplate，无论您希望如何实现它。

下面是一个示例：

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;
    }
}

在本例中，根据您的DataTemplate的优先级返回任何您想要的DataContext。

在xaml中，您需要告诉控件它应该使用什么DataTemplateSelector：

<ListBox Width="400" Margin="10"
         ItemsSource="{Binding Source={StaticResource myTodoList}}"
         ItemTemplateSelector="{StaticResource myDataTemplateSelector}"
         HorizontalContentAlignment="Stretch"/>

在本例中，myDataTemplateSelector将由ListBox使用。

在您的例子中，是MyButton。