Question

假设我希望通过XAML在UserControl上设置名称空间ns中的DataTemplate类型的附加属性“ Attached.Template”。有没有让我做到这一点的语法？以下是一些无效的内容：

<!-- fails; UserControl may have only one child -->
<UserControl>
   <ns:Attached.Template>
      <DataTemplate />
   </ns:Attached.Template>

   <Grid />
</UserControl>

<!-- fails; the '(' character cannot be included in a name -->
<UserControl>
   <UserControl.(ns:Attached.Template)>
      <DataTemplate />
   </UserControl.(ns:Attached.Template)>

   <Grid />
</UserControl>

<!-- fails; "UserControl.ns" is an undeclared prefix -->
<UserControl>
   <UserControl.ns:Attached.Template>
      <DataTemplate />
   </UserControl.ns:Attached.Template>

   <Grid />
</UserControl>

属性定义非常标准；只需遵循R＃的内置模板：

public static class Attached
{
    public static readonly DependencyProperty TemplateProperty = DependencyProperty.RegisterAttached(
        "Template", typeof(DataTemplate), typeof(Attached),
        new PropertyMetadata(default(DataTemplate)));

    public static void SetTemplate(DependencyObject element, DataTemplate value) =>
        element.SetValue(TemplateProperty, value);

    public static DataTemplate GetTemplate(DependencyObject element) =>
        (DataTemplate) element.GetValue(TemplateProperty);
}

Answer 1

似乎您必须像这样显式设置UserControl的Content：

<UserControl>
    <ns:Attached.Template>
        <DataTemplate/>
    </ns:Attached.Template>

    <UserControl.Content>
        <Grid/>
    </UserControl.Content>
</UserControl>

这也有效：

<UserControl>
    <Grid/>

    <ns:Attached.Template>
        <DataTemplate/>
    </ns:Attached.Template>
</UserControl>

IMO XAML解析器中的怪异错误或缺陷。

Answer 2

在DataTemplate中创建UserControl.Resources，然后给它一个Key，然后使用namespace:attatchedproperty={StaticResource Key}，您将能够实现我认为的要求。 / p>

使用元素语法在UserControl上设置附加属性值

2 个答案: