ItemTemplatePanel无法看到控件上的依赖属性
本文关键字:依赖 属性 控件 ItemTemplatePanel | 更新日期: 2023-09-27 17:54:33
所以当我使用下面的样式时,它按预期应用于我的控件。然而,GridView
(ItemsPanelTemplate
和ItemsTemplate
)内部的模板查看消费者为其数据上下文应用的视图模型。
问题是我想在控件中设置项的尺寸。
所以我的问题是,我如何将控件模板作为数据上下文应用于ItemsPanelTemplate
和ItemTemplate
?
我的第一个想法是使用祖先绑定,但这似乎不是UWP的特性。
My Control Class
public class FilterableImageWrapGrid : FilterableContentList
{
private GridView _partGridView;
public Point ItemDimensions
{
get { return (Point)GetValue(ItemDimensionsProperty); }
set { SetValue(ItemDimensionsProperty, value); }
}
// Using a DependencyProperty as the backing store for ItemDimensions. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ItemDimensionsProperty =
DependencyProperty.Register("ItemDimensions", typeof(Point), typeof(FilterableImageWrapGrid), new PropertyMetadata(new Point()));
public FilterableImageWrapGrid()
{
DefaultStyleKey = typeof(FilterableImageWrapGrid);
}
protected override void OnApplyTemplate()
{
_partGridView = GetTemplateChild("PART_FilterableImageList") as GridView;
base.OnApplyTemplate();
}
private static void OnItemDimensionsChanged(object sender, DependencyPropertyChangedEventArgs args)
{
FilterableImageWrapGrid wrapGrid = sender as FilterableImageWrapGrid;
if (wrapGrid != null && wrapGrid._partGridView != null)
{
wrapGrid._partGridView.ItemTemplate.SetValue(GridViewItem.WidthProperty, wrapGrid.ItemDimensions.X);
wrapGrid._partGridView.ItemTemplate.SetValue(GridViewItem.HeightProperty, wrapGrid.ItemDimensions.Y);
}
}
}
Generic中的样式。xaml文件
<Style TargetType="controls:FilterableImageWrapGrid">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Grid VerticalAlignment="Stretch">
<GridView
x:Name="PART_FilterableImageList"
ItemsSource="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}, Path=FilteredItems, Mode=TwoWay}"
SelectedItem="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}, Path=SelectedContentItem, Mode=TwoWay}">
<GridView.ItemContainerTransitions>
<TransitionCollection>
<EntranceThemeTransition IsStaggeringEnabled="True"/>
<AddDeleteThemeTransition />
<EdgeUIThemeTransition Edge="Left"/>
</TransitionCollection>
</GridView.ItemContainerTransitions>
<GridView.ItemsPanel>
<ItemsPanelTemplate>
<ItemsWrapGrid
x:Name="PART_ItemsWrapGrid"
ItemHeight="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}, Path=ItemDimensions.Y}"
ItemWidth="{Binding RelativeSource={RelativeSource Mode=TemplatedParent}, Path=ItemDimensions.X}"
Margin="2" Orientation="Horizontal"
HorizontalAlignment="Center"/>
</ItemsPanelTemplate>
</GridView.ItemsPanel>
<GridView.ItemTemplate>
<DataTemplate>
.... Data template that binds to the view model the consumer provides....
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
如果我理解正确的话,在模板内部的模板中绑定RelativeSource Mode=TemplatedParent
是行不通的。就是这样吗?
然后将ItemDimensions
属性定义为附加的依赖属性:
public class FilterableImageWrapGrid : FilterableContentList
public static Point GetItemDimensions(DependencyObject obj)
{
return (Point)obj.GetValue(ItemDimensionsProperty);
}
public static void SetItemDimensions(DependencyObject obj, Point value)
{
obj.SetValue(ItemDimensionsProperty, value);
}
public static readonly DependencyProperty ItemDimensionsProperty =
DependencyProperty.RegisterAttached("ItemDimensions", typeof(Point), typeof(ItemsWrapGrid), new PropertyMetadata(new Point()));
...
}
,然后添加到模板中:
<GridView
x:Name="PART_FilterableImageList"
...
<GridView.ItemsPanel>
<ItemsPanelTemplate>
<ItemsWrapGrid
x:Name="PART_ItemsWrapGrid"
ItemHeight="{Binding RelativeSource=
{RelativeSource Mode=Self}, Path=ItemDimensions.Y}"
ItemWidth="{Binding RelativeSource=
{RelativeSource Mode=Self}, Path=ItemDimensions.X}"
Margin="2" Orientation="Horizontal"
HorizontalAlignment="Center"/>
</ItemsPanelTemplate>
</GridView.ItemsPanel>
...
</GridView>
这就像一个可继承的属性(在uwp中还不存在?),你可以通过模板绑定手动向下推可视树到内部模板。