WPF Focus，无法同时获得逻辑和键盘焦点
WPF Focus, can't get both logical and keyboard focus
我看过其他几篇关于 WPF 和焦点的帖子，我认为我的代码中缺少一些东西。我正在开发一个使用严格 MVVM 的应用程序，所以我试图避免视图文件中的任何代码隐藏（在需要代码隐藏时使用附加行为），但此时甚至将焦点代码放在代码中 -在视图后面它不起作用。
我有一个带有主 window 的应用程序，我正在尝试在热键上搜索 window 弹出窗口。我希望只要用户按下热键，键盘焦点就会放在搜索文本上，所以它只是热键，然后键入您的搜索词。此时除了逻辑焦点之外的所有内容都在工作，即使键盘声称焦点在元素上。
我似乎无法通过代码让它同时获得键盘和逻辑焦点。但是，如果我在搜索框出现时立即按 Tab 键，我就会直接进入文本框。
主要window代码：
<ribbon:RibbonWindow x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ribbon="clr-namespace:Microsoft.Windows.Controls.Ribbon;assembly=RibbonControlsLibrary"
xmlns:attached="clr-namespace:UserInterface.Attached"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:command="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.WPF45"
xmlns:viewModels="clr-namespace:UserInterface.ViewModels"
xmlns:views="clr-namespace:UserInterface.Views"
xmlns:layout="clr-namespace:UserInterface.ViewModels.Layout"
xmlns:layout1="clr-namespace:UserInterface.Views.Layout"
MinHeight="560"
MinWidth="950"
WindowStartupLocation="CenterScreen"
Icon="{Binding Layout.IconPath}"
DataContext="{Binding Main, Source={StaticResource Locator}}"
FocusManager.FocusedElement="{Binding ElementName=LayoutControl}"
Title="{Binding Layout.Title}">
<!-- Ribbon menu shortcuts -->
<Window.InputBindings>
<KeyBinding Modifiers="Control" Key="T" Command="{Binding Layout.Commands[GlobalObjectSearch]}" />
</Window.InputBindings>
<Grid>
<ContentPresenter Content="{Binding Layout}" x:Name="LayoutControl">
<ContentPresenter.Resources>
<DataTemplate DataType="{x:Type layout:MainViewModel}">
<layout1:MainView/>
</DataTemplate>
</ContentPresenter.Resources>
</ContentPresenter>
</Grid>
</ribbon:RibbonWindow>
使搜索 window 出现的代码：
public SelfClosingDialogView ShowSelfClosingDialog(IWindowDialogViewModel dataContext)
{
dataContext.CheckWhetherArgumentIsNull(nameof(dataContext));
var view = new SelfClosingDialogView
{
DataContext = dataContext,
Owner = Application.Current?.MainWindow
};
view.Show();
return view;
}
搜索 window 代码（重复使用，如此通用）：
<Window x:Class="UserInterface.Views.DialogViews.SelfClosingDialogView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:attached="clr-namespace:UserInterface.Attached"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
mc:Ignorable="d"
SizeToContent="WidthAndHeight"
WindowStyle="None"
WindowStartupLocation="CenterOwner">
<!-- Allow view models to cause the window to close -->
<Window.Style>
<Style TargetType="{x:Type Window}">
<Style.Triggers>
<DataTrigger Binding="{Binding IsClosed}" Value="true">
<!-- Executes close -->
<Setter Property="attached:WindowCloseBehavior.Close" Value="true" />
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Style>
<!-- Displays the passed-in view model -->
<Grid>
<ContentPresenter x:Name="DialogPresenter" Content="{Binding}" Margin="0" />
</Grid>
</Window>
我的搜索视图代码：
<UserControl x:Class="UserInterface.Views.DialogViews.ObjectSearchView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:dialogViewModels="clr-namespace:UserInterface.ViewModels.DialogViewModels"
xmlns:utils="clr-namespace:WPF.Utils"
xmlns:attached="clr-namespace:UserInterface.Attached"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance dialogViewModels:ObjectSearchViewModel}"
MinWidth="250"
Focusable="True"
FocusManager.IsFocusScope="True">
<UserControl.InputBindings>
<KeyBinding Key="Enter" Command="{Binding BrowseToObjectCommand}" />
<KeyBinding Key="Escape" Command="{Binding CloseWindowCommand}" />
</UserControl.InputBindings>
<UserControl.Resources>
<Style BasedOn="{StaticResource FormTextBlockStyle}" TargetType="TextBlock" />
</UserControl.Resources>
<StackPanel>
<TextBox Name="SearchText"
Focusable="True"
Text="{utils:ValidatingLiveBinding SearchText}"
attached:NavigatingListBoxBehavior.LinkedListBox="{Binding ElementName=SearchResults}">
</TextBox>
<ScrollViewer HorizontalScrollBarVisibility="Hidden"
VerticalScrollBarVisibility="Auto"
MaxHeight="400">
<ListBox Name="SearchResults"
ItemsSource="{Binding SearchResults}"
SelectedItem="{Binding SelectedSearchItem}"
Visibility="{Binding HasSearchResults, Converter={StaticResource BooleanToVisibilityConverter}}"
attached:ItemsControlProperties.DoubleClickCommand="{Binding BrowseToObjectCommand}"
KeyboardNavigation.IsTabStop="False"
IsSynchronizedWithCurrentItem="True" />
</ScrollViewer>
</StackPanel>
</UserControl>
最后，我试图获得焦点的代码隐藏黑客（加上调试代码，这样我就不会失去焦点来回切换到 Visual Studio）：
public partial class ObjectSearchView : UserControl
{
public ObjectSearchView()
{
InitializeComponent();
this.Loaded += this.OnLoad;
}
private void OnLoad(object sender, RoutedEventArgs e)
{
this.PrintFocusInfo();
FocusManager.SetFocusedElement(FocusManager.GetFocusScope(this), this.SearchText);
this.PrintFocusInfo();
this.SearchText.Focus();
this.PrintFocusInfo();
Keyboard.Focus(this.SearchText);
this.PrintFocusInfo();
}
[Conditional("DEBUG")]
private void PrintFocusInfo()
{
var logicalElement = FocusManager.GetFocusedElement(FocusManager.GetFocusScope(this.SearchText));
Debug.WriteLine("Current logical focus is on '{0}', of type '{1}' ({2})".FormatInvariantCulture((logicalElement as FrameworkElement)?.Name, logicalElement?.GetType().Name, logicalElement));
var focusedElement = Keyboard.FocusedElement;
Debug.WriteLine(
"Current Keyboard Focus is on '{0}', of type '{1}' ({2})".FormatInvariantCulture(
(focusedElement as FrameworkElement)?.Name,
focusedElement.GetType().Name,
focusedElement));
}
}
输出window内容：
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on '', of type 'MainWindow' (UserInterface.Views.MainWindow)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on '', of type 'MainWindow' (UserInterface.Views.MainWindow)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on 'SearchText', of type 'TextBox' (System.Windows.Controls.TextBox)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on 'SearchText', of type 'TextBox' (System.Windows.Controls.TextBox)
我试图包括我能想到的所有内容，但我无法获得逻辑焦点来显示除 null 之外的任何内容。
这是我最终创建的行为，它为我解决了这个问题。还有很多我不知道为什么这有效......但是如果你在让 Focus 合作时遇到问题看起来关键是在 IsVisible 设置为 true 时抓住它，并让 Dispatcher 设置焦点为你。我将此事件链接到文本框上的 IsVisibleChanged 元素（通过附加行为）。
private void SetFocusOnVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if ((bool)e.NewValue)
{
this.Dispatcher.BeginInvoke(DispatcherPriority.ContextIdle, new Action(() => this.AssociatedObject.Focus()));
}
}
我看过其他几篇关于 WPF 和焦点的帖子，我认为我的代码中缺少一些东西。我正在开发一个使用严格 MVVM 的应用程序，所以我试图避免视图文件中的任何代码隐藏（在需要代码隐藏时使用附加行为），但此时甚至将焦点代码放在代码中 -在视图后面它不起作用。
我有一个带有主 window 的应用程序，我正在尝试在热键上搜索 window 弹出窗口。我希望只要用户按下热键，键盘焦点就会放在搜索文本上，所以它只是热键，然后键入您的搜索词。此时除了逻辑焦点之外的所有内容都在工作，即使键盘声称焦点在元素上。
我似乎无法通过代码让它同时获得键盘和逻辑焦点。但是，如果我在搜索框出现时立即按 Tab 键，我就会直接进入文本框。
主要window代码：
<ribbon:RibbonWindow x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ribbon="clr-namespace:Microsoft.Windows.Controls.Ribbon;assembly=RibbonControlsLibrary"
xmlns:attached="clr-namespace:UserInterface.Attached"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:command="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.WPF45"
xmlns:viewModels="clr-namespace:UserInterface.ViewModels"
xmlns:views="clr-namespace:UserInterface.Views"
xmlns:layout="clr-namespace:UserInterface.ViewModels.Layout"
xmlns:layout1="clr-namespace:UserInterface.Views.Layout"
MinHeight="560"
MinWidth="950"
WindowStartupLocation="CenterScreen"
Icon="{Binding Layout.IconPath}"
DataContext="{Binding Main, Source={StaticResource Locator}}"
FocusManager.FocusedElement="{Binding ElementName=LayoutControl}"
Title="{Binding Layout.Title}">
<!-- Ribbon menu shortcuts -->
<Window.InputBindings>
<KeyBinding Modifiers="Control" Key="T" Command="{Binding Layout.Commands[GlobalObjectSearch]}" />
</Window.InputBindings>
<Grid>
<ContentPresenter Content="{Binding Layout}" x:Name="LayoutControl">
<ContentPresenter.Resources>
<DataTemplate DataType="{x:Type layout:MainViewModel}">
<layout1:MainView/>
</DataTemplate>
</ContentPresenter.Resources>
</ContentPresenter>
</Grid>
</ribbon:RibbonWindow>
使搜索 window 出现的代码：
public SelfClosingDialogView ShowSelfClosingDialog(IWindowDialogViewModel dataContext)
{
dataContext.CheckWhetherArgumentIsNull(nameof(dataContext));
var view = new SelfClosingDialogView
{
DataContext = dataContext,
Owner = Application.Current?.MainWindow
};
view.Show();
return view;
}
搜索 window 代码（重复使用，如此通用）：
<Window x:Class="UserInterface.Views.DialogViews.SelfClosingDialogView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:attached="clr-namespace:UserInterface.Attached"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
mc:Ignorable="d"
SizeToContent="WidthAndHeight"
WindowStyle="None"
WindowStartupLocation="CenterOwner">
<!-- Allow view models to cause the window to close -->
<Window.Style>
<Style TargetType="{x:Type Window}">
<Style.Triggers>
<DataTrigger Binding="{Binding IsClosed}" Value="true">
<!-- Executes close -->
<Setter Property="attached:WindowCloseBehavior.Close" Value="true" />
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Style>
<!-- Displays the passed-in view model -->
<Grid>
<ContentPresenter x:Name="DialogPresenter" Content="{Binding}" Margin="0" />
</Grid>
</Window>
我的搜索视图代码：
<UserControl x:Class="UserInterface.Views.DialogViews.ObjectSearchView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:dialogViewModels="clr-namespace:UserInterface.ViewModels.DialogViewModels"
xmlns:utils="clr-namespace:WPF.Utils"
xmlns:attached="clr-namespace:UserInterface.Attached"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance dialogViewModels:ObjectSearchViewModel}"
MinWidth="250"
Focusable="True"
FocusManager.IsFocusScope="True">
<UserControl.InputBindings>
<KeyBinding Key="Enter" Command="{Binding BrowseToObjectCommand}" />
<KeyBinding Key="Escape" Command="{Binding CloseWindowCommand}" />
</UserControl.InputBindings>
<UserControl.Resources>
<Style BasedOn="{StaticResource FormTextBlockStyle}" TargetType="TextBlock" />
</UserControl.Resources>
<StackPanel>
<TextBox Name="SearchText"
Focusable="True"
Text="{utils:ValidatingLiveBinding SearchText}"
attached:NavigatingListBoxBehavior.LinkedListBox="{Binding ElementName=SearchResults}">
</TextBox>
<ScrollViewer HorizontalScrollBarVisibility="Hidden"
VerticalScrollBarVisibility="Auto"
MaxHeight="400">
<ListBox Name="SearchResults"
ItemsSource="{Binding SearchResults}"
SelectedItem="{Binding SelectedSearchItem}"
Visibility="{Binding HasSearchResults, Converter={StaticResource BooleanToVisibilityConverter}}"
attached:ItemsControlProperties.DoubleClickCommand="{Binding BrowseToObjectCommand}"
KeyboardNavigation.IsTabStop="False"
IsSynchronizedWithCurrentItem="True" />
</ScrollViewer>
</StackPanel>
</UserControl>
最后，我试图获得焦点的代码隐藏黑客（加上调试代码，这样我就不会失去焦点来回切换到 Visual Studio）：
public partial class ObjectSearchView : UserControl
{
public ObjectSearchView()
{
InitializeComponent();
this.Loaded += this.OnLoad;
}
private void OnLoad(object sender, RoutedEventArgs e)
{
this.PrintFocusInfo();
FocusManager.SetFocusedElement(FocusManager.GetFocusScope(this), this.SearchText);
this.PrintFocusInfo();
this.SearchText.Focus();
this.PrintFocusInfo();
Keyboard.Focus(this.SearchText);
this.PrintFocusInfo();
}
[Conditional("DEBUG")]
private void PrintFocusInfo()
{
var logicalElement = FocusManager.GetFocusedElement(FocusManager.GetFocusScope(this.SearchText));
Debug.WriteLine("Current logical focus is on '{0}', of type '{1}' ({2})".FormatInvariantCulture((logicalElement as FrameworkElement)?.Name, logicalElement?.GetType().Name, logicalElement));
var focusedElement = Keyboard.FocusedElement;
Debug.WriteLine(
"Current Keyboard Focus is on '{0}', of type '{1}' ({2})".FormatInvariantCulture(
(focusedElement as FrameworkElement)?.Name,
focusedElement.GetType().Name,
focusedElement));
}
}
输出window内容：
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on '', of type 'MainWindow' (UserInterface.Views.MainWindow)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on '', of type 'MainWindow' (UserInterface.Views.MainWindow)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on 'SearchText', of type 'TextBox' (System.Windows.Controls.TextBox)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on 'SearchText', of type 'TextBox' (System.Windows.Controls.TextBox)
我试图包括我能想到的所有内容，但我无法获得逻辑焦点来显示除 null 之外的任何内容。
这是我最终创建的行为，它为我解决了这个问题。还有很多我不知道为什么这有效......但是如果你在让 Focus 合作时遇到问题看起来关键是在 IsVisible 设置为 true 时抓住它，并让 Dispatcher 设置焦点为你。我将此事件链接到文本框上的 IsVisibleChanged 元素（通过附加行为）。
private void SetFocusOnVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if ((bool)e.NewValue)
{
this.Dispatcher.BeginInvoke(DispatcherPriority.ContextIdle, new Action(() => this.AssociatedObject.Focus()));
}
}