[英]How to find a resource in a UserControl from a DataTemplateSelector class in WPF?
我正在創建自己的UserControl,並且在我的XAML中的UserControl.Resources部分下有兩個不同的DataTemplates。 我想在這兩個datatemplates之間進行選擇,具體取決於listview中顯示的對象的屬性值。 我這樣做是通過創建一個自定義DataTemplateSelector類並重寫SelectTemplate方法,該方法應該返回我想要使用的DataTemplate。 但是,我不知道如何“查找”位於UserControls資源部分的數據模板,我看到的所有示例只從Window.Resources獲取數據模板。 在這個例子中,他們獲取當前的MainWindow然后使用FindResource來查找DataTemplate ,我如何以類似的方式獲取我的UserControl ?:
public override DataTemplate
SelectTemplate(object item, DependencyObject container)
{
if (item != null && item is AuctionItem)
{
AuctionItem auctionItem = item as AuctionItem;
Window window = Application.Current.MainWindow;
switch (auctionItem.SpecialFeatures)
{
case SpecialFeatures.None:
return
window.FindResource("AuctionItem_None")
as DataTemplate;
case SpecialFeatures.Color:
return
window.FindResource("AuctionItem_Color")
as DataTemplate;
}
}
return null;
}
上面的示例來自此處: ItemsControl.ItemTemplateSelector屬性
試試這個:
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
if (item != null && item is AuctionItem)
{
AuctionItem auctionItem = item as AuctionItem;
switch (auctionItem.SpecialFeatures)
{
case SpecialFeatures.None:
return
((FrameworkElement)container).FindResource("AuctionItem_None")
as DataTemplate;
case SpecialFeatures.Color:
return
((FrameworkElement)container).FindResource("AuctionItem_Color")
as DataTemplate;
}
}
return null;
}
我通常使用DataConmplateSelector的構造函數中的UserControl作為參數從后面的代碼實例化我的DataTemplateSelector,如下所示:
public class MyUserControl : UserControl
{
public MyUserControl()
{
Resources["MyDataTemplateSelector"] = new MyDataTemplateSelector(this);
InitializeComponent();
}
}
public class MyDataTemplateSelector : DataTemplateSelector
{
private MyUserControl parent;
public MyDataTemplateSelector(MyUserControl parent)
{
this.parent = parent;
}
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
parent.DoStuff();
}
}
不是鎮上最漂亮的女孩,但它完成了工作;)
希望這可以幫助!
<DataTemplate x:Key="addTemplate">
<Button Command="{Binding Path=AddCommand}">Add</Button>
</DataTemplate>
<DataTemplate x:Key="editTemplate">
<Button Command="{Binding Path=UpdateCommand}">Update</Button>
</DataTemplate>
<TemplateSelectors:AddEditTemplateSelector
AddTemplate="{StaticResource addTemplate}"
EditTemplate="{StaticResource editTemplate}"
x:Key="addEditTemplateSelector" />
僅限XAML!
WinRT和Windows Phone解決方案涉及向上移動可視樹,直到找到父控件:
protected override Windows.UI.Xaml.DataTemplate SelectTemplateCore(object item, Windows.UI.Xaml.DependencyObject container)
{
var parent = FindParent<MyParentControlType>(container as FrameworkElement);
if(parent != null)
{
if (item is Something)
return parent.Resources["TemplateForSomething"] as DataTemplate;
else if(item is SomethingElse)
return parent.Resources["TemplateForSomethingElse"] as DataTemplate;
else
// etc
}
else
{
return App.Current.Resources["SomeFallbackResource"] as DataTemplate;
}
}
public static T FindParent<T>(FrameworkElement element) where T : FrameworkElement
{
FrameworkElement parent = Windows.UI.Xaml.Media.VisualTreeHelper.GetParent(element) as FrameworkElement;
while (parent != null)
{
T correctlyTyped = parent as T;
if (correctlyTyped != null)
return correctlyTyped;
else
return FindParent<T>(parent);
}
return null;
}
FindParent方法基於這里接受的答案: 如何從ListViewItem獲取ListView?
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.