WPF和最初的焦点-Java 学习之路

167

似乎当WPF应用程序启动时，没有任何焦点 .

这真的很奇怪 . 我使用过的每个其他框架都符合您的期望：将初始重点放在Tab键顺序中的第一个控件上 . 但我已经确认它是WPF，而不仅仅是我的应用程序 - 如果我创建一个新窗口，只是在其中放置一个TextBox，并运行应用程序，TextBox没有焦点，直到我点击它或按Tab键 . 呸 .

我的实际应用程序比TextBox更复杂 . 我在UserControls中有几层UserControl . 其中一个UserControls有Focusable =“True”和KeyDown / KeyUp处理程序，我希望它在我的窗口打开后立即获得焦点 . 不过，我仍然有点像WPF新手，而且我没有太多运气搞清楚如何做到这一点 .

如果我启动我的应用程序并按Tab键，则焦点转到我的可聚焦控件，它开始以我想要的方式工作 . 但是我不希望我的用户在开始使用窗口之前必须点击Tab .

我玩过FocusManager.FocusedElement，但是我不确定将它设置为哪个控件（顶级窗口？包含可聚焦控件的父级？可聚焦控件本身？）或者设置它的内容 .

一旦窗口打开，我需要做什么才能使我的深层嵌套控件具有初始焦点？或者更好的是，将第一个可聚焦控件聚焦在Tab键顺序中？

12 回答

14
您可以轻松地将控件设置为XAML中的焦点元素 .
```
<Window>
   <DataGrid FocusManager.FocusedElement="{Binding RelativeSource={RelativeSource Self}}">
     ...
   </DataGrid>
</Window>
```
我从来没有尝试在用户控件中设置它，看看它是否有效，但它可能 .
回复于 2024-04-20T21:38:01+08:00
54
以上解决方案对我来说没有按预期工作，我稍微改变了Mizipzor提出的行为如下：

从这一部分
```
if ((bool)args.NewValue)
        {
            control.Loaded += (sender, e) =>
                   control.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
        }
```
对此
```
if ((bool)args.NewValue)
        {
            control.Loaded += (sender, e) => control.Focus();
        }
```
我没有将此行为附加到Window或UserControl，但控制我想最初聚焦，例如：
```
<TextBox ui:FocusBehavior.InitialFocus="True" />
```
哦，抱歉不同的命名我正在使用附加属性的InitialFocus名称 .

这对我有用，也许它可以帮助别人 .
回复于 2024-04-20T21:38:01+08:00

<Window FocusManager.FocusedElement="{Binding ElementName=yourControlName}">

回复于 2024-04-20T21:38:01+08:00

基于接受的answer实现为附加行为：

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace UI.Behaviors
{
    public static class FocusBehavior
    {
        public static readonly DependencyProperty FocusFirstProperty =
            DependencyProperty.RegisterAttached(
                "FocusFirst",
                typeof(bool),
                typeof(FocusBehavior),
                new PropertyMetadata(false, OnFocusFirstPropertyChanged));

        public static bool GetFocusFirst(Control control)
        {
            return (bool)control.GetValue(FocusFirstProperty);
        }

        public static void SetFocusFirst (Control control, bool value)
        {
            control.SetValue(FocusFirstProperty, value);
        }

        static void OnFocusFirstPropertyChanged(
            DependencyObject obj, DependencyPropertyChangedEventArgs args)
        {
            Control control = obj as Control;
            if (control == null || !(args.NewValue is bool))
            {
                return;
            }

            if ((bool)args.NewValue)
            {
                control.Loaded += (sender, e) =>
                    control.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
            }
        }
    }
}

像这样用它：

<Window xmlns:Behaviors="clr-namespace:UI.Behaviors"
        Behaviors:FocusBehavior.FocusFirst="true">

回复于 2024-04-20T21:38:01+08:00

135
我发现了另一种可能的解Mark Smith发布了一个FirstFocusedElement markup extension用于FocusManager.FocusedElement .
```
<UserControl x:Class="FocusTest.Page2"
    xmlns:FocusTest="clr-namespace:FocusTest"
    FocusManager.FocusedElement="{FocusTest:FirstFocusedElement}">
```
回复于 2024-04-20T21:38:01+08:00

有同样的问题通过简单的解决方案解决了它：在主窗口中：

<Window ....
        FocusManager.FocusedElement="{Binding ElementName=usercontrolelementname}"
         ... />

在用户控件中：

private void UserControl_GotFocus_1(object sender, RoutedEventArgs e)
        {
            targetcontrol.Focus();
            this.GotFocus -= UserControl_GotFocus_1;  // to set focus only once
        }

回复于 2024-04-20T21:38:01+08:00

-1

C＃6的最小版本Mizipzor's answer .

public static class FocusBehavior
{
    public static readonly DependencyProperty GiveInitialFocusProperty =
        DependencyProperty.RegisterAttached(
            "GiveInitialFocus",
            typeof(bool),
            typeof(FocusBehavior),
            new PropertyMetadata(false, OnFocusFirstPropertyChanged));

    public static bool GetGiveInitialFocus(Control control) => (bool)control.GetValue(GiveInitialFocusProperty);
    public static void SetGiveInitialFocus(Control control, bool value) => control.SetValue(GiveInitialFocusProperty, value);

    private static void OnFocusFirstPropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
    {
        var control = obj as Control;

        if (control == null || !(args.NewValue is bool))
            return;

        if ((bool)args.NewValue)
            control.Loaded += OnControlLoaded;
        else
            control.Loaded -= OnControlLoaded;
    }

    private static void OnControlLoaded(object sender, RoutedEventArgs e) => ((Control)sender).MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
}

在XAML中使用：

<Window local:FocusBehavior.GiveInitialFocus="True" />

回复于 2024-04-20T21:38:01+08:00

8
我有一个聪明的主意，就是通过Reflector来查看Focusable属性的使用位置，并找到了解决这个问题的方法 . 我只需要将以下代码添加到我的Window的构造函数中：
```
Loaded += (sender, e) =>
    MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
```
这将自动选择Tab键顺序中的第一个控件，因此它是一个通用的解决方案，应该可以放入任何窗口和Just Work .
回复于 2024-04-20T21:38:01+08:00
0
在有了“WPF初始焦点噩梦”并基于堆叠上的一些答案之后，以下证明了我是最佳解决方案 .

首先，添加您的App.xaml OnStartup（）以下内容：
```
EventManager.RegisterClassHandler(typeof(Window), Window.LoadedEvent,
          new RoutedEventHandler(WindowLoaded));
```
然后在App.xaml中添加'WindowLoaded'事件：
```
void WindowLoaded(object sender, RoutedEventArgs e)
    {
        var window = e.Source as Window;
        System.Threading.Thread.Sleep(100);
        window.Dispatcher.Invoke(
        new Action(() =>
        {
            window.MoveFocus(new TraversalRequest(FocusNavigationDirection.First));

        }));
    }
```
由于某些框架竞争条件，WPF初始焦点大多失败，因此必须使用线程问题 .

我发现以下解决方案最佳，因为它在整个应用程序中全局使用 .

希望能帮助到你...

奥兰
回复于 2024-04-20T21:38:01+08:00
8
如果你像我一样，并且你正在使用一些框架，以某种方式，搞乱基本的焦点行为，并使所有解决方案无关紧要，你仍然可以这样做：

1 - 注意获得焦点的元素（无论它是什么！）

2 - 在xxx.xaml.cs后面的代码中添加它
```
private bool _firstLoad;
```
3 - 在获得第一个焦点的元素上添加它：
```
GotFocus="Element_GotFocus"
```
4 - 在后面的代码中添加Element_GotFocus方法，并指定需要第一个焦点的WPF命名元素：
```
private void Element_GotFocus(object sender, RoutedEventArgs e)
{
    if(_firstLoad)
    {
        this.MyElementWithFistFocus.Focus();
        _firstLoad = false;
    }
}
```
5 - 管理已加载的事件

在XAML中
```
Loaded="MyWindow_Loaded"
```
在xaml.cs中
```
private void MyWindow_Loaded(object sender, RoutedEventArgs e)
{
        _firstLoad = true;
        this.Element_GotFocus(null, null);
}
```
希望这将有助于作为最后的解决方案
回复于 2024-04-20T21:38:01+08:00

我也遇到了同样的问题 . 我在canvas容器中有三个文本框，并希望在用户控件打开时聚焦第一个文本框 . WPF代码遵循MVVM模式 . 我创建了一个单独的行为类来聚焦元素，并将其绑定到我的视图中 .

画布行为代码

public  class CanvasLoadedBehavior : Behavior<Canvas>
{
    private Canvas _canvas;
    protected override void OnAttached()
    {
        base.OnAttached();
        _canvas = AssociatedObject as Canvas;
        if (_canvas.Name == "ReturnRefundCanvas")
        {

            _canvas.Loaded += _canvas_Loaded;
        }


    }

    void _canvas_Loaded(object sender, RoutedEventArgs e)
    {
        FocusNavigationDirection focusDirection = FocusNavigationDirection.Next;

        // MoveFocus takes a TraveralReqest as its argument.
        TraversalRequest request = new TraversalRequest(focusDirection);
        UIElement elementWithFocus = Keyboard.FocusedElement as UIElement;
        if (elementWithFocus != null)
        {
            elementWithFocus.MoveFocus(request);
        }

    }

}

视图代码

<Canvas  Name="ReturnRefundCanvas" Height="200" Width="1466" DataContext="{Binding RefundSearchViewModel}">
                <i:Interaction.Behaviors>
                    <b:CanvasLoadedBehavior />
                </i:Interaction.Behaviors>
                <uc:Keyboard Canvas.Left="973" Canvas.Top="111" ToolTip="Keyboard" RenderTransformOrigin="-2.795,9.787"></uc:Keyboard>
                <Label  Style="{StaticResource Devlbl}" Canvas.Left="28" Content="Return and Refund Search" Canvas.Top="10" />
                <Image Height="30" Width="28" Canvas.Top="6" Canvas.Left="5" Source="pack://application:,,,/HomaKiosk;component/images/searchF.png">
                    <Image.OpacityMask>
                        <ImageBrush ImageSource="pack://application:,,,/HomaKiosk;component/images/searchF.png"/>
                    </Image.OpacityMask>
                </Image>

                <Separator Height="4" Canvas.Left="6" Margin="0" Canvas.Top="35" Width="1007"/>

                <ContentControl Canvas.Top="45" Canvas.Left="21"
                    ContentTemplate="{StaticResource ErrorMsg}"
                    Visibility="{Binding Error, Converter={c:StringNullOrEmptyToVisibilityConverter}}" 
                    Content="{Binding Error}" Width="992"></ContentControl>

                <Label  Style="{StaticResource Devlbl}" Canvas.Left="29" Name="FirstName" Content="First Name" Canvas.Top="90" />
                <wpf:AutoCompleteTextBox  Style="{StaticResource AutoComp}" Height="32" Canvas.Left="33" ToolTip="First Name"  Canvas.Top="120" Width="205"                     Padding="10,5" TabIndex="1001"
                    VerticalAlignment="Top"

                    Watermark=""
                    IconPlacement="Left"
                    IconVisibility="Visible"
                    Delay="100"

                    Text="{Binding FirstName, Mode=TwoWay, TargetNullValue=''}" 
                    Provider="{Binding FirstNameSuggestions}">
                    <wpf:AutoCompleteTextBox.ItemTemplate>
                        <DataTemplate>
                            <Border Padding="5">
                                <StackPanel Orientation="Vertical">
                                    <TextBlock Text="{Binding}"
                   FontWeight="Bold" />
                                </StackPanel>
                            </Border>
                        </DataTemplate>
                    </wpf:AutoCompleteTextBox.ItemTemplate>
                </wpf:AutoCompleteTextBox>

                <Label Style="{StaticResource Devlbl}" Canvas.Left="250" Content="Last Name" Canvas.Top="90" />
                <wpf:AutoCompleteTextBox  Style="{StaticResource AutoComp}" Height="32" ToolTip="Last Name" Canvas.Left="250"  Canvas.Top="120" Width="205" Padding="10,5"  TabIndex="1002"
                    VerticalAlignment="Top"
                    Watermark=""
                    IconPlacement="Left"
                    IconVisibility="Visible"
                    Delay="100"
                   Text="{Binding LastName, Mode=TwoWay, TargetNullValue=''}" 
                    Provider="{Binding LastNameSuggestions}">
                    <wpf:AutoCompleteTextBox.ItemTemplate>
                        <DataTemplate>
                            <Border Padding="5">
                                <StackPanel Orientation="Vertical">
                                    <TextBlock Text="{Binding}"
                   FontWeight="Bold" />
                                </StackPanel>
                            </Border>
                        </DataTemplate>
                    </wpf:AutoCompleteTextBox.ItemTemplate>
                </wpf:AutoCompleteTextBox>

                <Label Style="{StaticResource Devlbl}" Canvas.Left="480" Content="Receipt No" Canvas.Top="90" />
                             <wpf:AutoCompleteTextBox  Style="{StaticResource AutoComp}" Height="32" ToolTip="Receipt No" Canvas.Left="480"  Canvas.Top="120" Width="205" Padding="10,5"  TabIndex="1002"
                    VerticalAlignment="Top"
                    Watermark=""
                    IconPlacement="Left"
                    IconVisibility="Visible"
                    Delay="100"
                    Text="{Binding ReceiptNo, Mode=TwoWay, TargetNullValue=''}" 
                    Provider="{Binding ReceiptIdSuggestions}">
                    <wpf:AutoCompleteTextBox.ItemTemplate>
                        <DataTemplate>
                            <Border Padding="5">
                                <StackPanel Orientation="Vertical" >
                                    <TextBlock Text="{Binding}"
                   FontWeight="Bold">

                                    </TextBlock>
                                </StackPanel>
                            </Border>
                        </DataTemplate>
                    </wpf:AutoCompleteTextBox.ItemTemplate>
                    <i:Interaction.Behaviors>
                        <b:AllowableCharactersTextBoxBehavior RegularExpression="^[0-9]+$" MaxLength="15" />
                    </i:Interaction.Behaviors>
                </wpf:AutoCompleteTextBox>
                <!--<Label Style="{StaticResource Devlbl}" Canvas.Left="710" Content="Duration" Canvas.Top="79" />-->
                <!--<ComboBox AllowDrop="True" Canvas.Left="710" ToolTip="Duration" Canvas.Top="107" Width="205" TabIndex="1004"
                    Style="{StaticResource CommonComboBox}"      
                    ItemsSource="{Binding Durations}" DisplayMemberPath="Description" SelectedValuePath="Id" SelectedValue="{Binding SelectedDate, Mode=TwoWay}">

                </ComboBox>-->

                <Button Content="Search" Style="{StaticResource MyButton}" ToolTip="Search" 
                    Canvas.Top="116" Canvas.Left="710" Cursor="Hand" 
                    Command="{Binding SearchCommand}" TabIndex="2001">
                </Button>
                <Button Content="Clear" Style="{StaticResource MyButton}"  ToolTip="Clear"
                    Canvas.Top="116" Canvas.Left="840" Cursor="Hand" 
                    Command="{Binding ClearCommand}" TabIndex="2002">
                </Button>
                <Image Height="25" Width="25" Canvas.Top="175" Canvas.Left="25" Source="pack://application:,,,/HomaKiosk;component/images/chkpending.png"/>
                <Label  Style="{StaticResource LegendLbl}" Canvas.Left="50" Content="Check Returned and Payment Pending" Canvas.Top="178" />
                <Image Height="25" Width="25" Canvas.Top="175" Canvas.Left="300" Source="pack://application:,,,/HomaKiosk;component/images/chkrepaid.png"/>
                <Label  Style="{StaticResource LegendLbl}" Canvas.Left="325" Content="Repaid" Canvas.Top="178" />
                <Image Height="25" Width="25" Canvas.Top="175" Canvas.Left="395" Source="pack://application:,,,/HomaKiosk;component/images/refund.png"/>
                <Label  Style="{StaticResource LegendLbl}" Canvas.Left="415" Content="Refunded" Canvas.Top="178" />
                 </Canvas>

回复于 2024-04-20T21:38:01+08:00

149

这也有效：

<Window FocusManager.FocusedElement="{Binding ElementName=SomeElement}">

   <DataGrid x:Name="SomeElement">
     ...
   </DataGrid>
</Window>

回复于 2024-04-20T21:38:01+08:00

WPF和最初的焦点

12 回答

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