[英]How to change a property of a specific element in a DataTemplate from code behind?
[英]How to get element in code behind from DataTemplate
我有一個 FlipView 控件,其 DataTemplate 定義如下:
<FlipView x:Name="FlipView5Horizontal" Width="480" Height="270" BorderBrush="Black" BorderThickness="1" Style="{StaticResource FlipViewStyle1}">
<FlipView.ItemTemplate>
<DataTemplate>
<Grid>
<Image Width="480" Name="xxxImage" Height="270" Source="{Binding Image}" Stretch="UniformToFill"/>
<Border Name="xxxBorder" Background="#A5000000" Height="80" VerticalAlignment="Bottom">
<TextBlock Name="xxxTB" Text="{Binding Title}" FontFamily="Segoe UI" FontSize="26.667" Foreground="#CCFFFFFF" Padding="15,20"/>
</Border>
</Grid>
</DataTemplate>
</FlipView.ItemTemplate>
</FlipView>
在我后面的代碼中,我需要訪問名為“xxxTB”的 TextBlock。 這是我的代碼:
public IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
{
if (depObj != null)
{
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
{
DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
if (child != null && child is T)
{
yield return (T)child;
}
foreach (T childOfChild in FindVisualChildren<T>(child))
{
yield return childOfChild;
}
}
}
}
public void TestMethod()
{
foreach (var item in FindVisualChildren<TextBlock>(this))
{
if (timeLine.Name == "xxxTB")
{ }
}
}
但是,當它在 VisualTree 中找到 FlipView 時,它返回: for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
因為VisualTreeHelper.GetChildrenCount(depObj)
不返回任何內容。
任何的想法?
所以這是一個有效的解決方案:
public void TestMethod()
{
DataTemplate dt = FlipView5Horizontal.ItemTemplate;
DependencyObject dio = dt.LoadContent();
foreach (var timeLine in FindVisualChildren<TextBlock>(dio)) //FindVisualTree is defined in the question :)
{
if (timeLine.Name == "xxxTB")
{ }
}
}
現在,我至少能夠加載控件。 (但是,我讀到由於某種原因,不應在重寫的方法 OnApplyTemplate 中使用此技巧)。
嘗試這個
ContentPresenter cp = GetFrameworkElementByName<ContentPresenter>(FlipView5Horizontal);
DataTemplate dt = FlipView5Horizontal.ItemTemplate;
TextBlock l = (dt.FindName("xxxTB", cp)) as TextBlock;
private static T GetFrameworkElementByName<T>(FrameworkElement referenceElement) where T : FrameworkElement
{
FrameworkElement child = null;
for (Int32 i = 0; i < VisualTreeHelper.GetChildrenCount(referenceElement); i++)
{
child = VisualTreeHelper.GetChild(referenceElement, i) as FrameworkElement;
System.Diagnostics.Debug.WriteLine(child);
if (child != null && child.GetType() == typeof(T))
{
break;
}
else if (child != null)
{
child = GetFrameworkElementByName<T>(child);
if (child != null && child.GetType() == typeof(T))
{
break;
}
}
}
return child as T;
}
你可以試試這個:
var textblock = IteratingKeyboardChildren(g, keyName);
Border IteratingKeyboardChildren(Grid g, string keyName)
{
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(g); i++)
{
var child = VisualTreeHelper.GetChild(g, i);
if (child is TextBlock )
{
if ((child as TextBlock ).Tag.ToString().Equals( keyName))
return child as TextBlock ;
}
}
return null;
}
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