当我在WPF MVVM应用程序中按Enter键而不是Tab键时，我想移动到下一个控件。我怎样才能做到这一点？
下面是我为此使用的附加属性。
首先，示例用法：
<TextBox Width="100"
Text="{Binding Name, Mode=TwoWay}"
UI:FocusAdvancement.AdvancesByEnterKey="True" />
(UI是我定义以下内容的名称空间别名。(
所附财产：
public static class FocusAdvancement
{
public static bool GetAdvancesByEnterKey(DependencyObject obj)
{
return (bool)obj.GetValue(AdvancesByEnterKeyProperty);
}
public static void SetAdvancesByEnterKey(DependencyObject obj, bool value)
{
obj.SetValue(AdvancesByEnterKeyProperty, value);
}
public static readonly DependencyProperty AdvancesByEnterKeyProperty =
DependencyProperty.RegisterAttached("AdvancesByEnterKey", typeof(bool), typeof(FocusAdvancement),
new UIPropertyMetadata(OnAdvancesByEnterKeyPropertyChanged));
static void OnAdvancesByEnterKeyPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var element = d as UIElement;
if(element == null) return;
if ((bool)e.NewValue) element.KeyDown += Keydown;
else element.KeyDown -= Keydown;
}
static void Keydown(object sender, KeyEventArgs e)
{
if(!e.Key.Equals(Key.Enter)) return;
var element = sender as UIElement;
if(element != null) element.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
}
}
你还说"而不是tab"，所以我想知道你是否想抑制以通常方式使用tab的能力。我建议不要这样做，因为这是一种常见的、众所周知的范式，但如果是这样的话，您可以在附加的属性中添加一个PreviewKeyDown处理程序，检查tab键，并为事件参数设置Handled = true。
如果你只想让它适用于几个文本框，周的答案是最好的。
如果你想让整个应用程序都以这种方式运行，makwana.a的答案更好，但可以改进。
以下是我对makwana.a答案的修改，我已经在许多应用中使用过它。它还支持在活动控件为复选框的情况下通过回车移动到下一个控件。我没有使用标记属性来决定焦点是否应该移动，而是使用了文本框的AcceptsReturn属性。我这样做是因为它默认为false，并且只在多行文本框中设置为true。在这种情况下，您无论如何都不希望焦点移动到回车时的下一个控件。
在App.xaml 的OnStartup void中声明这些事件处理程序
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.KeyDownEvent, new KeyEventHandler(TextBox_KeyDown));
EventManager.RegisterClassHandler(typeof(CheckBox), CheckBox.KeyDownEvent, new KeyEventHandler(CheckBox_KeyDown));
以下是使其在应用程序范围内工作所需的其余方法。
void TextBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter & (sender as TextBox).AcceptsReturn == false) MoveToNextUIElement(e);
}
void CheckBox_KeyDown(object sender, KeyEventArgs e)
{
MoveToNextUIElement(e);
//Sucessfully moved on and marked key as handled.
//Toggle check box since the key was handled and
//the checkbox will never receive it.
if (e.Handled == true)
{
CheckBox cb = (CheckBox)sender;
cb.IsChecked = !cb.IsChecked;
}
}
void MoveToNextUIElement(KeyEventArgs e)
{
// Creating a FocusNavigationDirection object and setting it to a
// local field that contains the direction selected.
FocusNavigationDirection focusDirection = FocusNavigationDirection.Next;
// MoveFocus takes a TraveralReqest as its argument.
TraversalRequest request = new TraversalRequest(focusDirection);
// Gets the element with keyboard focus.
UIElement elementWithFocus = Keyboard.FocusedElement as UIElement;
// Change keyboard focus.
if (elementWithFocus != null)
{
if (elementWithFocus.MoveFocus(request)) e.Handled = true;
}
}
编辑
我更新了代码，如果移动成功，则将击键标记为已处理，并且由于键已处理且将不再到达，因此我还切换复选框。
示例解决方案：在堆栈面板中使用PreviewKeyDown。预览。。。是一个气泡，因此事件可以在更高级别上处理。对于不同的元素类型，您可能需要以不同的方式处理这一问题，比如按钮，它似乎应该保留回车键，而不是将焦点更改为回车键。
这是xaml:
<StackPanel PreviewKeyDown="StackPanel_PreviewKeyDown" >
<TextBox >
Hello
</TextBox>
<TextBox>
World
</TextBox>
<TextBox>
test
</TextBox>
</StackPanel>
下面是代码：
private void StackPanel_PreviewKeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter)
{
TextBox s = e.Source as TextBox;
if (s != null)
{
s.MoveFocus(new TraversalRequest( FocusNavigationDirection.Next));
}
e.Handled = true;
}
}
这只是一个概念验证的沙盒。
快乐编码。。。
希望得到帮助：使用AttachedPropertyhttp://madprops.org/blog/enter-to-tab-as-an-attached-property/
public class EnterKeyTraversal
{
public static bool GetIsEnabled(DependencyObject obj)
{
return (bool)obj.GetValue(IsEnabledProperty);
}
public static void SetIsEnabled(DependencyObject obj, bool value)
{
obj.SetValue(IsEnabledProperty, value);
}
static void ue_PreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
{
var ue = e.OriginalSource as FrameworkElement;
if (e.Key == Key.Enter)
{
e.Handled = true;
ue.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
}
}
private static void ue_Unloaded(object sender, RoutedEventArgs e)
{
var ue = sender as FrameworkElement;
if (ue == null) return;
ue.Unloaded -= ue_Unloaded;
ue.PreviewKeyDown -= ue_PreviewKeyDown;
}
public static readonly DependencyProperty IsEnabledProperty =
DependencyProperty.RegisterAttached("IsEnabled", typeof(bool),
typeof(EnterKeyTraversal), new UIPropertyMetadata(false, IsEnabledChanged));
static void IsEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var ue = d as FrameworkElement;
if (ue == null) return;
if ((bool)e.NewValue)
{
ue.Unloaded += ue_Unloaded;
ue.PreviewKeyDown += ue_PreviewKeyDown;
}
else
{
ue.PreviewKeyDown -= ue_PreviewKeyDown;
}
}
}
<StackPanel my:EnterKeyTraversal.IsEnabled="True">
在应用程序文件的onstartup事件中编写此代码
EventManager.RegisterClassHandler(GetType(TextBox), TextBox.KeyDownEvent, New RoutedEventHandler(AddressOf TextBox_KeyDown))
然后将TextBox_KeyDown子定义为
Private Sub TextBox_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Input.KeyEventArgs)
If e.Key = Key.Enter And TryCast(sender, TextBox).Tag <> "1" Then
' Creating a FocusNavigationDirection object and setting it to a
' local field that contains the direction selected.
Dim focusDirection As FocusNavigationDirection = FocusNavigationDirection.Next
' MoveFocus takes a TraveralReqest as its argument.
Dim request As New TraversalRequest(focusDirection)
' Gets the element with keyboard focus.
Dim elementWithFocus As UIElement = TryCast(Keyboard.FocusedElement, UIElement)
' Change keyboard focus.
If elementWithFocus IsNot Nothing Then
elementWithFocus.MoveFocus(request)
End If
End If
End Sub
我使用了文本框的"标记"属性来跳过移动焦点。也就是说，如果您不想在按下回车键时移动到下一个控件(在多行文本框的情况下，需要回车来创建新行(。只需将标记属性设置为1。
第一个将触发器添加到PreviewKeyDown激发时将调用的每个元素。还要添加Dependency属性并绑定您习惯于将焦点放在的FrameworkElement。在触发器中，为绑定的元素提供设置Focus。
使用代码隐藏：
我想出了下面的代码。请注意，它没有设置e.Handled。此外，MoveFocus_Next不会返回移动焦点是否成功，而是返回参数是否为null。您可以根据需要添加或删除要处理的控件类型。该代码是为应用程序的MainWindow编写的，但也处理其他窗口。您还可以调整代码以从App_Startup事件进行调用。
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
public partial class MainWindow : Window
{
private bool MoveFocus_Next(UIElement uiElement)
{
if (uiElement != null)
{
uiElement.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
return true;
}
return false;
}
public MainWindow()
{
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
EventManager.RegisterClassHandler(typeof(Window), Window.PreviewKeyUpEvent, new KeyEventHandler(Window_PreviewKeyUp));
}
private void Window_PreviewKeyUp(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter)
{
IInputElement inputElement = Keyboard.FocusedElement;
if (inputElement != null)
{
System.Windows.Controls.Primitives.TextBoxBase textBoxBase = inputElement as System.Windows.Controls.Primitives.TextBoxBase;
if (textBoxBase != null)
{
if (!textBoxBase.AcceptsReturn)
MoveFocus_Next(textBoxBase);
return;
}
if (
MoveFocus_Next(inputElement as ComboBox)
||
MoveFocus_Next(inputElement as Button)
||
MoveFocus_Next(inputElement as DatePicker)
||
MoveFocus_Next(inputElement as CheckBox)
||
MoveFocus_Next(inputElement as DataGrid)
||
MoveFocus_Next(inputElement as TabItem)
||
MoveFocus_Next(inputElement as RadioButton)
||
MoveFocus_Next(inputElement as ListBox)
||
MoveFocus_Next(inputElement as ListView)
||
MoveFocus_Next(inputElement as PasswordBox)
||
MoveFocus_Next(inputElement as Window)
||
MoveFocus_Next(inputElement as Page)
||
MoveFocus_Next(inputElement as Frame)
)
return;
}
}
}
}