如何在单击其中的按钮时不关闭 xtk:SplitButton 的自定义弹出窗口？
How to not close a xtk:SplitButton's custom Popup when a click is made on a button inside it?
我有一个自定义控件，它覆盖了 OnApplyTemplate。在其中我试图访问子模板的子模板，但它们似乎没有被加载。我希望的是：当 xtk:SplitButton 的 Popup 内的 PART_IncreaseButton 被点击时， Popup 不会关闭，只是让 Button 对点击做出反应.
CustomIntegerUpDown 和 CustomSplitButton 派生自 Xceed Extended WPF Toolkit。 CustomIntegerUpDown 没有改变样式或模板或代码隐藏，目前它的唯一目的是做我上面说的，但我才刚刚开始。以下是所有相关来源。
我试过这个：
IncrementButton = Utils.FindChild<RepeatButton>(PartPopup, "PART_IncreaseButton")
之后 IncrementButton 为 null，尽管在 Immediate Window:
Utils.FindChild<Popup>(this, "PART_Popup") return 从 GetTemplateChild("PART_Popup") 获得的 Popup。
然后
Utils.FindChild<ButtonSpinner>(PartPopup, "PART_Spinner") returns null.
Utils.FindChild<CustomIntegerUpDown>(PartPopup, "MyCustomIntegerUpDown") return null.
VisualTreeHelper.GetChildrenCount(PartPopup) returns 0.
PartPopup.ApplyTemplate() returns false.
我也看过 但我不确定是否值得尝试这种方式。
FindChild是这个（取自here）：
/// <summary>
/// Finds a Child of a given item in the visual tree.
/// </summary>
/// <param name="parent">A direct parent of the queried item.</param>
/// <typeparam name="T">The type of the queried item.</typeparam>
/// <param name="childName">x:Name or Name of child. </param>
/// <returns>The first parent item that matches the submitted type parameter.
/// If not matching item can be found,
/// a null parent is being returned.</returns>
public static T FindChild<T>(System.Windows.DependencyObject parent, string childName)
where T : System.Windows.DependencyObject
{
// Confirm parent and childName are valid.
if (parent == null) return null;
T foundChild = null;
int childrenCount = System.Windows.Media.VisualTreeHelper.GetChildrenCount(parent);
for (int i = 0; i < childrenCount; i++)
{
var child = System.Windows.Media.VisualTreeHelper.GetChild(parent, i);
// If the child is not of the request child type child
T childType = child as T;
if (childType == null)
{
// recursively drill down the tree
foundChild = FindChild<T>(child, childName);
// If the child is found, break so we do not overwrite the found child.
if (foundChild != null) break;
}
else if (!string.IsNullOrEmpty(childName))
{
var frameworkElement = child as System.Windows.FrameworkElement;
// If the child's name is set for search
if (frameworkElement != null && frameworkElement.Name == childName)
{
// if the child's name is of the request name
foundChild = (T)child;
break;
}
}
else
{
// child element found.
foundChild = (T)child;
break;
}
}
return foundChild;
}
在 CustomSplitButton.xaml.cs 我有这个：
internal Popup PartPopup;
internal Button PartButtonWith1, PartButtonWith5, PartButtonWith10, PartButtonWithCustom;
internal RepeatButton IncrementButton;
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
PartPopup = (Popup)GetTemplateChild("PART_Popup");
PartButtonWith1 = (Button)GetTemplateChild("PART_ButtonWith1");
PartButtonWith5 = (Button)GetTemplateChild("PART_ButtonWith5");
PartButtonWith10 = (Button)GetTemplateChild("PART_ButtonWith10");
PartButtonWithCustom = (Button)GetTemplateChild("PART_ButtonWithCustom");
PartPopup.ApplyTemplate();
IncrementButton = Utils.FindChild<RepeatButton>(PartPopup, "PART_IncreaseButton");
if (PartPopup != null)
{
PartPopup.PreviewMouseDown += PART_Popup_PreviewMouseUp;
PartPopup.PreviewMouseUp += PART_Popup_PreviewMouseUp;
}
if (PartButtonWith1 != null)
{
PartButtonWith1.Click += Btns_NewTimer_Click;
}
if (PartButtonWith5 != null)
{
PartButtonWith5.Click += Btns_NewTimer_Click;
}
if (PartButtonWith10 != null)
{
PartButtonWith10.Click += Btns_NewTimer_Click;
}
if (PartButtonWithCustom != null)
{
PartButtonWithCustom.Click += BtnCustom_Click;
}
}
视觉树是这样的：
CustomSplitButton的样式如下(xmlns:xtkThemes="clr-namespace:Xceed.Wpf.Toolkit.Themes;assembly=Xceed.Wpf.Toolkit"):
<Style x:Key="AddCountSplitButtonStyle" TargetType="{x:Type xtk:SplitButton}">
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="IsTabStop" Value="False"/>
<Setter Property="HorizontalContentAlignment" Value="Center"/>
<Setter Property="VerticalContentAlignment" Value="Center"/>
<Setter Property="Background" Value="{DynamicResource {ComponentResourceKey ResourceId=ButtonNormalBackgroundKey, TypeInTargetAssembly={x:Type xtkThemes:ResourceKeys}}}"/>
<Setter Property="BorderBrush" Value="{DynamicResource {ComponentResourceKey ResourceId=ButtonNormalOuterBorderKey, TypeInTargetAssembly={x:Type xtkThemes:ResourceKeys}}}"/>
<Setter Property="DropDownContentBackground">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFF0F0F0" Offset="0"/>
<GradientStop Color="#FFE5E5E5" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="Padding" Value="3"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type xtk:SplitButton}">
<Grid x:Name="MainGrid" SnapsToDevicePixels="True">
<xtk:ButtonChrome x:Name="ControlChrome" BorderThickness="0" Background="{TemplateBinding Background}" RenderEnabled="{TemplateBinding IsEnabled}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Button x:Name="PART_ActionButton" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="0" Padding="{TemplateBinding Padding}" Style="{x:Null}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}">
<Button.Template>
<ControlTemplate TargetType="{x:Type Button}">
<ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}"/>
</ControlTemplate>
</Button.Template>
<Grid>
<xtk:ButtonChrome x:Name="ActionButtonChrome" BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" Foreground="{TemplateBinding Foreground}" RenderMouseOver="{Binding IsMouseOver, ElementName=PART_ActionButton}" RenderPressed="{Binding IsPressed, ElementName=PART_ActionButton}" RenderEnabled="{TemplateBinding IsEnabled}">
<xtk:ButtonChrome.BorderThickness>
<Binding ConverterParameter="2" Path="BorderThickness" RelativeSource="{RelativeSource TemplatedParent}">
<Binding.Converter>
<xtk:ThicknessSideRemovalConverter/>
</Binding.Converter>
</Binding>
</xtk:ButtonChrome.BorderThickness>
<ContentPresenter x:Name="ActionButtonContent" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</xtk:ButtonChrome>
</Grid>
</Button>
<ToggleButton x:Name="PART_ToggleButton" Grid.Column="1" IsChecked="{Binding IsOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
<ToggleButton.IsHitTestVisible>
<Binding Path="IsOpen" RelativeSource="{RelativeSource TemplatedParent}">
<Binding.Converter>
<xtk:InverseBoolConverter/>
</Binding.Converter>
</Binding>
</ToggleButton.IsHitTestVisible>
<ToggleButton.Template>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}"/>
</ControlTemplate>
</ToggleButton.Template>
<Grid>
<xtk:ButtonChrome x:Name="ToggleButtonChrome" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Padding="1,0" RenderMouseOver="{Binding IsMouseOver, ElementName=PART_ToggleButton}" RenderPressed="{Binding IsPressed, ElementName=PART_ToggleButton}" RenderChecked="{TemplateBinding IsOpen}" RenderEnabled="{TemplateBinding IsEnabled}">
<Grid x:Name="arrowGlyph" IsHitTestVisible="False" Margin="4,3">
<Path x:Name="Arrow" Data="M0,0L3,0 4.5,1.5 6,0 9,0 4.5,4.5z" Fill="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" Height="5" Margin="0,1,0,0" Width="9"/>
</Grid>
</xtk:ButtonChrome>
</Grid>
</ToggleButton>
</Grid>
</xtk:ButtonChrome>
<Popup x:Name="PART_Popup" AllowsTransparency="True" Focusable="False" HorizontalOffset="1" IsOpen="{Binding IsChecked, ElementName=PART_ToggleButton}" Placement="{TemplateBinding DropDownPosition}" VerticalOffset="1"
StaysOpen="False">
<Border BorderThickness="{DynamicResource DefaultBorderThickness}" Margin="10,0,10,10" Background="{DynamicResource DarkerBaseBrush}" BorderBrush="{DynamicResource PopupBorderBrush}" CornerRadius="{DynamicResource DefaultCornerRadius}">
<Grid MinWidth="100" Name="PART_ContentPresenter">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Button x:Name="PART_ButtonWith1" Grid.Row="0" Grid.ColumnSpan="2">
1
</Button>
<Button x:Name="PART_ButtonWith5" Grid.Row="1" Grid.ColumnSpan="2">
5
</Button>
<Button x:Name="PART_ButtonWith10" Grid.Row="2" Grid.ColumnSpan="2">
10
</Button>
<local:CustomIntegerUpDown Grid.Row="3" Value="1"
Increment="1" ClipValueToMinMax="True"
x:Name="MyCustomIntegerUpDown">
</local:CustomIntegerUpDown>
<Button x:Name="PART_ButtonWithCustom" Grid.Row="3" Grid.Column="1" Padding="2,2,2,2">
>
</Button>
</Grid>
<Border.Effect>
<DropShadowEffect ShadowDepth="0" BlurRadius="10" Color="{DynamicResource Base6Color}" />
</Border.Effect>
</Border>
</Popup>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Fill" TargetName="Arrow" Value="#FFAFAFAF"/>
<Setter Property="Foreground" TargetName="ActionButtonChrome" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
在 OnApplyTemplate 中，我希望能够访问 this 中模板中的子模板。但是我没有找到办法做到这一点。
我的相关问题here。
更新 1
示例的起点，已更新（它使用 BionicCode 的答案中的 TryFindVisualChildElementByName 扩展方法）：
internal Popup PartPopup;
internal Button PartButtonWith1, PartButtonWith5, PartButtonWith10, PartButtonWithCustom;
internal RepeatButton IncrementButton;
private void SplitButton_Loaded(object sender, RoutedEventArgs e)
{
PartPopup = (Popup)GetTemplateChild("PART_Popup");
PartButtonWith1 = (Button)GetTemplateChild("PART_ButtonWith1");
PartButtonWith5 = (Button)GetTemplateChild("PART_ButtonWith5");
PartButtonWith10 = (Button)GetTemplateChild("PART_ButtonWith10");
PartButtonWithCustom = (Button)GetTemplateChild("PART_ButtonWithCustom");
if (PartPopup != null)
{
PartPopup.ApplyTemplateRecursively();
if (PartPopup.TryFindVisualChildElementByName("PART_IncreaseButton", out FrameworkElement incButton))
{
IncrementButton = (RepeatButton)incButton;
// do something with IncrementButton here
}
PartPopup.PreviewMouseDown += PART_Popup_PreviewMouseUp;
PartPopup.PreviewMouseUp += PART_Popup_PreviewMouseUp;
}
if (PartButtonWith1 != null)
{
PartButtonWith1.Click += Btns_NewTimer_Click;
}
if (PartButtonWith5 != null)
{
PartButtonWith5.Click += Btns_NewTimer_Click;
}
if (PartButtonWith10 != null)
{
PartButtonWith10.Click += Btns_NewTimer_Click;
}
if (PartButtonWithCustom != null)
{
PartButtonWithCustom.Click += BtnCustom_Click;
}
}
上面使用的ApplyTemplateRecursively扩展方法，有2个版本：
无效版本
有没有可能让这个版本以某种方式工作？我觉得效率更高
/// <summary>
/// Not working because the ApplyTemplate affects the VisualTree and when applying
/// templates recursively it does not see the correct updated visual tree to be able
/// to continue.
/// </summary>
/// <param name="root"></param>
internal static void ApplyTemplateRecursively(this System.Windows.DependencyObject root)
{
if (root is System.Windows.Controls.Primitives.Popup p)
{
p.Child.ApplyTemplateRecursively();
return;
}
if (root is FrameworkElement r)
{
r.ApplyTemplate();
}
foreach (object element in System.Windows.LogicalTreeHelper.GetChildren(root))
{
if (element is System.Windows.DependencyObject el)
{
ApplyTemplateRecursively(el);
}
}
}
工作版本
/// <summary>
/// I am not sure if this is sufficiently efficient, because it goes through the entire visual tree.
/// </summary>
/// <param name="root"></param>
internal static void ApplyTemplateRecursively(this System.Windows.DependencyObject root)
{
if (root is System.Windows.Controls.Primitives.Popup p)
{
p.Child.ApplyTemplateRecursively();
return;
}
if (root is FrameworkElement r)
{
r.ApplyTemplate();
}
for (int i = 0; i < System.Windows.Media.VisualTreeHelper.GetChildrenCount(root); ++i)
{
DependencyObject d = VisualTreeHelper.GetChild(root, i);
ApplyTemplateRecursively(d);
}
}
现在我正在尝试解决实际问题。
更新 2
我已举报this issue。
重点是 Popup 的内容不直接是可视化树的一部分。这就是为什么寻找 Popup 的视觉 children 总是 return null。一个Popup的内容单独渲染，赋值给Popup.Child属性。在继续 Popup 中的树遍历之前，您需要从 Child 属性 中提取它们。
以下是 return 与给定名称匹配的第一个 child 元素的自定义可视树帮助器方法。这个助手在 Popup 元素中正确搜索。此方法是 DependencyObject 类型的扩展方法，必须放入 static class:
public static bool TryFindVisualChildElementByName(
this DependencyObject parent,
string childElementName,
out FrameworkElement resultElement)
{
resultElement = null;
if (parent is Popup popup)
{
parent = popup.Child;
if (parent == null)
{
return false;
}
}
for (var childIndex = 0; childIndex < VisualTreeHelper.GetChildrenCount(parent); childIndex++)
{
DependencyObject childElement = VisualTreeHelper.GetChild(parent, childIndex);
if (childElement is FrameworkElement uiElement && uiElement.Name.Equals(
childElementName,
StringComparison.OrdinalIgnoreCase))
{
resultElement = uiElement;
return true;
}
if (childElement.TryFindVisualChildElementByName(childElementName, out resultElement))
{
return true;
}
}
return false;
}
这是一个扩展方法，它的用法是这样的：
CustomSplitButton.xaml.cs
// Constructor
public CustomSplitButton()
{
this.Loaded += GetParts;
}
private void GetParts(object sender, RoutedEventArgs e)
{
if (this.TryFindVisualChildElementByName("PART_Popup", out FrameworkElement popupPart))
{
if (popupPart.TryFindVisualChildElementByName("PART_ContentPresenter", out FrameworkElement contentPresenter))
{
if (!contentPresenter.IsLoaded)
{
contentPresenter.Loaded += CompleteSearch;
}
else
{
CompleteSearch(contentPresenter, null);
}
}
}
}
private void CompleteSearch(object sender, RoutedEventArgs e)
{
contentPresenter.Loaded -= CompleteSearch;
if ((sender as DependencyObject).TryFindVisualChildElementByName("PART_IncreaseButton", out FrameworkElement increaseButton))
{
IncrementButton = (RepeatButton) increaseButton;
}
}
备注
在 一个 parent 元素是 Loaded 之后搜索 非常重要。
这适用于可视化树中的所有元素。由于 SplitButton 包含一个默认折叠的下拉列表，因此并非所有内容都在最初加载。打开下拉列表后，SplitButton 使其内容可见，这会将它们添加到可视化树中。到目前为止，SplitButton.IsLoaded 属性 将 return false，表示按钮的不完整视觉状态。你需要做的是，一旦遇到 FrameworkElement where FrameworkElement.IsLoaded returns false 你必须订阅 FrameworkElement.Loaded 事件。在此处理程序中，您可以继续可视化树遍历。
Popup 类似的元素或折叠的控件增加了视觉树遍历的复杂性。
编辑：单击内容时保持Popup打开
既然你已经告诉我你在 ToolBar 中使用 SplitButton，我马上就知道你问题的根源了：
Classes in WPF which are focus scopes by default are Window, MenuItem, ToolBar, and ContextMenu.
[Microsoft Docs: Logical Focus]
只需从 ToolBar 中删除焦点范围，以防止在单击其任何内容（收到逻辑焦点）后立即从 Popup 中删除焦点：
<ToolBar FocusManager.IsFocusScope="False">
<CustomSplitButton />
</ToolBar>
编辑：在 Popup 打开
时，单击 PART_ToggleButton 时保持 Popup 打开
要防止 Popup 在 Popup 打开时单击 PART_ToggleButton 时关闭和重新打开，您需要处理鼠标按下事件（应用程序范围内）和自己打开弹出窗口。
首先修改 PART_Popup 使其保持打开状态，并从 IsOpen 属性:
中删除绑定
CustomSplitButton.xaml
<Popup x:Name="PART_Popup"
IsOpen="False"
StaysOpen="True"
AllowsTransparency="True"
Focusable="False"
HorizontalOffset="1"
Placement="{TemplateBinding DropDownPosition}"
VerticalOffset="1">
然后在您的 CustomSplitButton 中观察鼠标设备的鼠标按下事件并确定命中目标。我假设您检索了基础 PART_Popup 和 PART_ToggleButton 元素并将其存储在名为 属性 的PartPopup 和 PartToggleButton（请参阅本答案的第一部分了解如何操作）：
CustomSplitButton.xaml.cs
public CustomSplitButton()
{
this.Loaded += OnLoaded;
}
private void OnLoaded(object sender, RoutedEventArgs e)
{
Mouse.AddPreviewMouseDownHandler(Application.Current.MainWindow, KeepPopupOpen);
}
private void KeepPopupOpen(object sender, RoutedEventArgs routedEventArgs)
{
var mouseClickSourceElement = routedEventArgs.OriginalSource as DependencyObject;
var isPopupContentClicked = false;
var isPartToggleButtonClicked =
object.ReferenceEquals(routedEventArgs.Source, this)
&& mouseClickSourceElement.TryFindVisualParentElement(out ButtonBase button)
&& button.Name.Equals(this.PartToggleButton.Name, StringComparison.OrdinalIgnoreCase);
if (!isPartToggleButtonClicked)
{
isPopupContentClicked =
object.ReferenceEquals(routedEventArgs.Source, this)
&& mouseClickSourceElement.TryFindVisualParentElementByName("PART_ContentPresenter", out FrameworkElement popupContentPresenter));
}
this.PartPopup.IsOpen = this.IsOpen = isPartToggleButtonClicked || isPopupContentClicked ;
}
扩展方法 按类型和名称查找视觉对象 parent
public static class HelperExtensions
{
public static bool TryFindVisualParentElement<TParent>(this DependencyObject child, out TParent resultElement)
where TParent : DependencyObject
{
resultElement = null;
if (child == null)
{
return false;
}
DependencyObject parentElement = VisualTreeHelper.GetParent(child);
if (parentElement is TParent parent)
{
resultElement = parent;
return true;
}
return parentElement.TryFindVisualParentElement(out resultElement);
}
public static bool TryFindVisualParentElementByName(
this DependencyObject child,
string elementName,
out FrameworkElement resultElement)
{
resultElement = null;
if (child == null)
{
return false;
}
DependencyObject parentElement = VisualTreeHelper.GetParent(child);
if (parentElement is FrameworkElement frameworkElement &&
frameworkElement.Name.Equals(elementName, StringComparison.OrdinalIgnoreCase))
{
resultElement = frameworkElement;
return true;
}
return parentElement.TryFindVisualParentElementByName(elementName, out resultElement);
}
}
}
我有一个自定义控件，它覆盖了 OnApplyTemplate。在其中我试图访问子模板的子模板，但它们似乎没有被加载。我希望的是：当 xtk:SplitButton 的 Popup 内的 PART_IncreaseButton 被点击时， Popup 不会关闭，只是让 Button 对点击做出反应.
CustomIntegerUpDown 和 CustomSplitButton 派生自 Xceed Extended WPF Toolkit。 CustomIntegerUpDown 没有改变样式或模板或代码隐藏，目前它的唯一目的是做我上面说的，但我才刚刚开始。以下是所有相关来源。
我试过这个：
IncrementButton = Utils.FindChild<RepeatButton>(PartPopup, "PART_IncreaseButton")
之后 IncrementButton 为 null，尽管在 Immediate Window:
Utils.FindChild<Popup>(this, "PART_Popup") return 从 GetTemplateChild("PART_Popup") 获得的 Popup。
然后
Utils.FindChild<ButtonSpinner>(PartPopup, "PART_Spinner") returns null.
Utils.FindChild<CustomIntegerUpDown>(PartPopup, "MyCustomIntegerUpDown") return null.
VisualTreeHelper.GetChildrenCount(PartPopup) returns 0.
PartPopup.ApplyTemplate() returns false.
我也看过
FindChild是这个（取自here）：
/// <summary>
/// Finds a Child of a given item in the visual tree.
/// </summary>
/// <param name="parent">A direct parent of the queried item.</param>
/// <typeparam name="T">The type of the queried item.</typeparam>
/// <param name="childName">x:Name or Name of child. </param>
/// <returns>The first parent item that matches the submitted type parameter.
/// If not matching item can be found,
/// a null parent is being returned.</returns>
public static T FindChild<T>(System.Windows.DependencyObject parent, string childName)
where T : System.Windows.DependencyObject
{
// Confirm parent and childName are valid.
if (parent == null) return null;
T foundChild = null;
int childrenCount = System.Windows.Media.VisualTreeHelper.GetChildrenCount(parent);
for (int i = 0; i < childrenCount; i++)
{
var child = System.Windows.Media.VisualTreeHelper.GetChild(parent, i);
// If the child is not of the request child type child
T childType = child as T;
if (childType == null)
{
// recursively drill down the tree
foundChild = FindChild<T>(child, childName);
// If the child is found, break so we do not overwrite the found child.
if (foundChild != null) break;
}
else if (!string.IsNullOrEmpty(childName))
{
var frameworkElement = child as System.Windows.FrameworkElement;
// If the child's name is set for search
if (frameworkElement != null && frameworkElement.Name == childName)
{
// if the child's name is of the request name
foundChild = (T)child;
break;
}
}
else
{
// child element found.
foundChild = (T)child;
break;
}
}
return foundChild;
}
在 CustomSplitButton.xaml.cs 我有这个：
internal Popup PartPopup;
internal Button PartButtonWith1, PartButtonWith5, PartButtonWith10, PartButtonWithCustom;
internal RepeatButton IncrementButton;
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
PartPopup = (Popup)GetTemplateChild("PART_Popup");
PartButtonWith1 = (Button)GetTemplateChild("PART_ButtonWith1");
PartButtonWith5 = (Button)GetTemplateChild("PART_ButtonWith5");
PartButtonWith10 = (Button)GetTemplateChild("PART_ButtonWith10");
PartButtonWithCustom = (Button)GetTemplateChild("PART_ButtonWithCustom");
PartPopup.ApplyTemplate();
IncrementButton = Utils.FindChild<RepeatButton>(PartPopup, "PART_IncreaseButton");
if (PartPopup != null)
{
PartPopup.PreviewMouseDown += PART_Popup_PreviewMouseUp;
PartPopup.PreviewMouseUp += PART_Popup_PreviewMouseUp;
}
if (PartButtonWith1 != null)
{
PartButtonWith1.Click += Btns_NewTimer_Click;
}
if (PartButtonWith5 != null)
{
PartButtonWith5.Click += Btns_NewTimer_Click;
}
if (PartButtonWith10 != null)
{
PartButtonWith10.Click += Btns_NewTimer_Click;
}
if (PartButtonWithCustom != null)
{
PartButtonWithCustom.Click += BtnCustom_Click;
}
}
视觉树是这样的：
CustomSplitButton的样式如下(xmlns:xtkThemes="clr-namespace:Xceed.Wpf.Toolkit.Themes;assembly=Xceed.Wpf.Toolkit"):
<Style x:Key="AddCountSplitButtonStyle" TargetType="{x:Type xtk:SplitButton}">
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="IsTabStop" Value="False"/>
<Setter Property="HorizontalContentAlignment" Value="Center"/>
<Setter Property="VerticalContentAlignment" Value="Center"/>
<Setter Property="Background" Value="{DynamicResource {ComponentResourceKey ResourceId=ButtonNormalBackgroundKey, TypeInTargetAssembly={x:Type xtkThemes:ResourceKeys}}}"/>
<Setter Property="BorderBrush" Value="{DynamicResource {ComponentResourceKey ResourceId=ButtonNormalOuterBorderKey, TypeInTargetAssembly={x:Type xtkThemes:ResourceKeys}}}"/>
<Setter Property="DropDownContentBackground">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFF0F0F0" Offset="0"/>
<GradientStop Color="#FFE5E5E5" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="Padding" Value="3"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type xtk:SplitButton}">
<Grid x:Name="MainGrid" SnapsToDevicePixels="True">
<xtk:ButtonChrome x:Name="ControlChrome" BorderThickness="0" Background="{TemplateBinding Background}" RenderEnabled="{TemplateBinding IsEnabled}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Button x:Name="PART_ActionButton" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="0" Padding="{TemplateBinding Padding}" Style="{x:Null}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}">
<Button.Template>
<ControlTemplate TargetType="{x:Type Button}">
<ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}"/>
</ControlTemplate>
</Button.Template>
<Grid>
<xtk:ButtonChrome x:Name="ActionButtonChrome" BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" Foreground="{TemplateBinding Foreground}" RenderMouseOver="{Binding IsMouseOver, ElementName=PART_ActionButton}" RenderPressed="{Binding IsPressed, ElementName=PART_ActionButton}" RenderEnabled="{TemplateBinding IsEnabled}">
<xtk:ButtonChrome.BorderThickness>
<Binding ConverterParameter="2" Path="BorderThickness" RelativeSource="{RelativeSource TemplatedParent}">
<Binding.Converter>
<xtk:ThicknessSideRemovalConverter/>
</Binding.Converter>
</Binding>
</xtk:ButtonChrome.BorderThickness>
<ContentPresenter x:Name="ActionButtonContent" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</xtk:ButtonChrome>
</Grid>
</Button>
<ToggleButton x:Name="PART_ToggleButton" Grid.Column="1" IsChecked="{Binding IsOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
<ToggleButton.IsHitTestVisible>
<Binding Path="IsOpen" RelativeSource="{RelativeSource TemplatedParent}">
<Binding.Converter>
<xtk:InverseBoolConverter/>
</Binding.Converter>
</Binding>
</ToggleButton.IsHitTestVisible>
<ToggleButton.Template>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}"/>
</ControlTemplate>
</ToggleButton.Template>
<Grid>
<xtk:ButtonChrome x:Name="ToggleButtonChrome" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Padding="1,0" RenderMouseOver="{Binding IsMouseOver, ElementName=PART_ToggleButton}" RenderPressed="{Binding IsPressed, ElementName=PART_ToggleButton}" RenderChecked="{TemplateBinding IsOpen}" RenderEnabled="{TemplateBinding IsEnabled}">
<Grid x:Name="arrowGlyph" IsHitTestVisible="False" Margin="4,3">
<Path x:Name="Arrow" Data="M0,0L3,0 4.5,1.5 6,0 9,0 4.5,4.5z" Fill="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" Height="5" Margin="0,1,0,0" Width="9"/>
</Grid>
</xtk:ButtonChrome>
</Grid>
</ToggleButton>
</Grid>
</xtk:ButtonChrome>
<Popup x:Name="PART_Popup" AllowsTransparency="True" Focusable="False" HorizontalOffset="1" IsOpen="{Binding IsChecked, ElementName=PART_ToggleButton}" Placement="{TemplateBinding DropDownPosition}" VerticalOffset="1"
StaysOpen="False">
<Border BorderThickness="{DynamicResource DefaultBorderThickness}" Margin="10,0,10,10" Background="{DynamicResource DarkerBaseBrush}" BorderBrush="{DynamicResource PopupBorderBrush}" CornerRadius="{DynamicResource DefaultCornerRadius}">
<Grid MinWidth="100" Name="PART_ContentPresenter">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Button x:Name="PART_ButtonWith1" Grid.Row="0" Grid.ColumnSpan="2">
1
</Button>
<Button x:Name="PART_ButtonWith5" Grid.Row="1" Grid.ColumnSpan="2">
5
</Button>
<Button x:Name="PART_ButtonWith10" Grid.Row="2" Grid.ColumnSpan="2">
10
</Button>
<local:CustomIntegerUpDown Grid.Row="3" Value="1"
Increment="1" ClipValueToMinMax="True"
x:Name="MyCustomIntegerUpDown">
</local:CustomIntegerUpDown>
<Button x:Name="PART_ButtonWithCustom" Grid.Row="3" Grid.Column="1" Padding="2,2,2,2">
>
</Button>
</Grid>
<Border.Effect>
<DropShadowEffect ShadowDepth="0" BlurRadius="10" Color="{DynamicResource Base6Color}" />
</Border.Effect>
</Border>
</Popup>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Fill" TargetName="Arrow" Value="#FFAFAFAF"/>
<Setter Property="Foreground" TargetName="ActionButtonChrome" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
在 OnApplyTemplate 中，我希望能够访问 this 中模板中的子模板。但是我没有找到办法做到这一点。
我的相关问题here。
更新 1
示例的起点，已更新（它使用 BionicCode 的答案中的 TryFindVisualChildElementByName 扩展方法）：
internal Popup PartPopup;
internal Button PartButtonWith1, PartButtonWith5, PartButtonWith10, PartButtonWithCustom;
internal RepeatButton IncrementButton;
private void SplitButton_Loaded(object sender, RoutedEventArgs e)
{
PartPopup = (Popup)GetTemplateChild("PART_Popup");
PartButtonWith1 = (Button)GetTemplateChild("PART_ButtonWith1");
PartButtonWith5 = (Button)GetTemplateChild("PART_ButtonWith5");
PartButtonWith10 = (Button)GetTemplateChild("PART_ButtonWith10");
PartButtonWithCustom = (Button)GetTemplateChild("PART_ButtonWithCustom");
if (PartPopup != null)
{
PartPopup.ApplyTemplateRecursively();
if (PartPopup.TryFindVisualChildElementByName("PART_IncreaseButton", out FrameworkElement incButton))
{
IncrementButton = (RepeatButton)incButton;
// do something with IncrementButton here
}
PartPopup.PreviewMouseDown += PART_Popup_PreviewMouseUp;
PartPopup.PreviewMouseUp += PART_Popup_PreviewMouseUp;
}
if (PartButtonWith1 != null)
{
PartButtonWith1.Click += Btns_NewTimer_Click;
}
if (PartButtonWith5 != null)
{
PartButtonWith5.Click += Btns_NewTimer_Click;
}
if (PartButtonWith10 != null)
{
PartButtonWith10.Click += Btns_NewTimer_Click;
}
if (PartButtonWithCustom != null)
{
PartButtonWithCustom.Click += BtnCustom_Click;
}
}
上面使用的ApplyTemplateRecursively扩展方法，有2个版本：
无效版本
有没有可能让这个版本以某种方式工作？我觉得效率更高
/// <summary>
/// Not working because the ApplyTemplate affects the VisualTree and when applying
/// templates recursively it does not see the correct updated visual tree to be able
/// to continue.
/// </summary>
/// <param name="root"></param>
internal static void ApplyTemplateRecursively(this System.Windows.DependencyObject root)
{
if (root is System.Windows.Controls.Primitives.Popup p)
{
p.Child.ApplyTemplateRecursively();
return;
}
if (root is FrameworkElement r)
{
r.ApplyTemplate();
}
foreach (object element in System.Windows.LogicalTreeHelper.GetChildren(root))
{
if (element is System.Windows.DependencyObject el)
{
ApplyTemplateRecursively(el);
}
}
}
工作版本
/// <summary>
/// I am not sure if this is sufficiently efficient, because it goes through the entire visual tree.
/// </summary>
/// <param name="root"></param>
internal static void ApplyTemplateRecursively(this System.Windows.DependencyObject root)
{
if (root is System.Windows.Controls.Primitives.Popup p)
{
p.Child.ApplyTemplateRecursively();
return;
}
if (root is FrameworkElement r)
{
r.ApplyTemplate();
}
for (int i = 0; i < System.Windows.Media.VisualTreeHelper.GetChildrenCount(root); ++i)
{
DependencyObject d = VisualTreeHelper.GetChild(root, i);
ApplyTemplateRecursively(d);
}
}
现在我正在尝试解决实际问题。
更新 2
我已举报this issue。
重点是 Popup 的内容不直接是可视化树的一部分。这就是为什么寻找 Popup 的视觉 children 总是 return null。一个Popup的内容单独渲染，赋值给Popup.Child属性。在继续 Popup 中的树遍历之前，您需要从 Child 属性 中提取它们。
以下是 return 与给定名称匹配的第一个 child 元素的自定义可视树帮助器方法。这个助手在 Popup 元素中正确搜索。此方法是 DependencyObject 类型的扩展方法，必须放入 static class:
public static bool TryFindVisualChildElementByName(
this DependencyObject parent,
string childElementName,
out FrameworkElement resultElement)
{
resultElement = null;
if (parent is Popup popup)
{
parent = popup.Child;
if (parent == null)
{
return false;
}
}
for (var childIndex = 0; childIndex < VisualTreeHelper.GetChildrenCount(parent); childIndex++)
{
DependencyObject childElement = VisualTreeHelper.GetChild(parent, childIndex);
if (childElement is FrameworkElement uiElement && uiElement.Name.Equals(
childElementName,
StringComparison.OrdinalIgnoreCase))
{
resultElement = uiElement;
return true;
}
if (childElement.TryFindVisualChildElementByName(childElementName, out resultElement))
{
return true;
}
}
return false;
}
这是一个扩展方法，它的用法是这样的：
CustomSplitButton.xaml.cs
// Constructor
public CustomSplitButton()
{
this.Loaded += GetParts;
}
private void GetParts(object sender, RoutedEventArgs e)
{
if (this.TryFindVisualChildElementByName("PART_Popup", out FrameworkElement popupPart))
{
if (popupPart.TryFindVisualChildElementByName("PART_ContentPresenter", out FrameworkElement contentPresenter))
{
if (!contentPresenter.IsLoaded)
{
contentPresenter.Loaded += CompleteSearch;
}
else
{
CompleteSearch(contentPresenter, null);
}
}
}
}
private void CompleteSearch(object sender, RoutedEventArgs e)
{
contentPresenter.Loaded -= CompleteSearch;
if ((sender as DependencyObject).TryFindVisualChildElementByName("PART_IncreaseButton", out FrameworkElement increaseButton))
{
IncrementButton = (RepeatButton) increaseButton;
}
}
备注
在 一个 parent 元素是 Loaded 之后搜索 非常重要。
这适用于可视化树中的所有元素。由于 SplitButton 包含一个默认折叠的下拉列表，因此并非所有内容都在最初加载。打开下拉列表后，SplitButton 使其内容可见，这会将它们添加到可视化树中。到目前为止，SplitButton.IsLoaded 属性 将 return false，表示按钮的不完整视觉状态。你需要做的是，一旦遇到 FrameworkElement where FrameworkElement.IsLoaded returns false 你必须订阅 FrameworkElement.Loaded 事件。在此处理程序中，您可以继续可视化树遍历。
Popup 类似的元素或折叠的控件增加了视觉树遍历的复杂性。
编辑：单击内容时保持Popup打开
既然你已经告诉我你在 ToolBar 中使用 SplitButton，我马上就知道你问题的根源了：
Classes in WPF which are focus scopes by default are
Window,MenuItem,ToolBar, andContextMenu. [Microsoft Docs: Logical Focus]
只需从 ToolBar 中删除焦点范围，以防止在单击其任何内容（收到逻辑焦点）后立即从 Popup 中删除焦点：
<ToolBar FocusManager.IsFocusScope="False">
<CustomSplitButton />
</ToolBar>
编辑：在 Popup 打开
时，单击 PART_ToggleButton 时保持 Popup 打开
要防止 Popup 在 Popup 打开时单击 PART_ToggleButton 时关闭和重新打开，您需要处理鼠标按下事件（应用程序范围内）和自己打开弹出窗口。
首先修改 PART_Popup 使其保持打开状态，并从 IsOpen 属性:
CustomSplitButton.xaml
<Popup x:Name="PART_Popup"
IsOpen="False"
StaysOpen="True"
AllowsTransparency="True"
Focusable="False"
HorizontalOffset="1"
Placement="{TemplateBinding DropDownPosition}"
VerticalOffset="1">
然后在您的 CustomSplitButton 中观察鼠标设备的鼠标按下事件并确定命中目标。我假设您检索了基础 PART_Popup 和 PART_ToggleButton 元素并将其存储在名为 属性 的PartPopup 和 PartToggleButton（请参阅本答案的第一部分了解如何操作）：
CustomSplitButton.xaml.cs
public CustomSplitButton()
{
this.Loaded += OnLoaded;
}
private void OnLoaded(object sender, RoutedEventArgs e)
{
Mouse.AddPreviewMouseDownHandler(Application.Current.MainWindow, KeepPopupOpen);
}
private void KeepPopupOpen(object sender, RoutedEventArgs routedEventArgs)
{
var mouseClickSourceElement = routedEventArgs.OriginalSource as DependencyObject;
var isPopupContentClicked = false;
var isPartToggleButtonClicked =
object.ReferenceEquals(routedEventArgs.Source, this)
&& mouseClickSourceElement.TryFindVisualParentElement(out ButtonBase button)
&& button.Name.Equals(this.PartToggleButton.Name, StringComparison.OrdinalIgnoreCase);
if (!isPartToggleButtonClicked)
{
isPopupContentClicked =
object.ReferenceEquals(routedEventArgs.Source, this)
&& mouseClickSourceElement.TryFindVisualParentElementByName("PART_ContentPresenter", out FrameworkElement popupContentPresenter));
}
this.PartPopup.IsOpen = this.IsOpen = isPartToggleButtonClicked || isPopupContentClicked ;
}
扩展方法 按类型和名称查找视觉对象 parent
public static class HelperExtensions
{
public static bool TryFindVisualParentElement<TParent>(this DependencyObject child, out TParent resultElement)
where TParent : DependencyObject
{
resultElement = null;
if (child == null)
{
return false;
}
DependencyObject parentElement = VisualTreeHelper.GetParent(child);
if (parentElement is TParent parent)
{
resultElement = parent;
return true;
}
return parentElement.TryFindVisualParentElement(out resultElement);
}
public static bool TryFindVisualParentElementByName(
this DependencyObject child,
string elementName,
out FrameworkElement resultElement)
{
resultElement = null;
if (child == null)
{
return false;
}
DependencyObject parentElement = VisualTreeHelper.GetParent(child);
if (parentElement is FrameworkElement frameworkElement &&
frameworkElement.Name.Equals(elementName, StringComparison.OrdinalIgnoreCase))
{
resultElement = frameworkElement;
return true;
}
return parentElement.TryFindVisualParentElementByName(elementName, out resultElement);
}
}
}