如果我从GotFocus事件处理程序中调用SelectAll，它对鼠标不起作用——鼠标一释放，选择就消失了。
编辑:人们喜欢唐纳利的回答，我将试着解释为什么我不像公认的答案那样喜欢它。
It is more complex, while the accepted answer does the same thing in a simpler way.
The usability of accepted answer is better. When you click in the middle of the text, text gets unselected when you release the mouse allowing you to start editing instantly, and if you still want to select all, just press the button again and this time it will not unselect on release. Following Donelle's recipe, if I click in the middle of text, I have to click second time to be able to edit. If I click somewhere within the text versus outside of the text, this most probably means I want to start editing instead of overwriting everything.
我选择了部分Donnelle的答案(跳过双击)，因为我认为这更自然。然而，像grokies一样，我不喜欢创建派生类的需要。但我也不喜欢Grokys的OnStartup方法。我需要在“一般但不总是”的基础上这样做。
我已经实现了这作为一个附加的DependencyProperty，所以我可以设置local:SelectTextOnFocus。在xaml中Active =“True”。我觉得这种方式最令人愉快。
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
public class SelectTextOnFocus : DependencyObject
{
public static readonly DependencyProperty ActiveProperty = DependencyProperty.RegisterAttached(
"Active",
typeof(bool),
typeof(SelectTextOnFocus),
new PropertyMetadata(false, ActivePropertyChanged));
private static void ActivePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (d is TextBox)
{
TextBox textBox = d as TextBox;
if ((e.NewValue as bool?).GetValueOrDefault(false))
{
textBox.GotKeyboardFocus += OnKeyboardFocusSelectText;
textBox.PreviewMouseLeftButtonDown += OnMouseLeftButtonDown;
}
else
{
textBox.GotKeyboardFocus -= OnKeyboardFocusSelectText;
textBox.PreviewMouseLeftButtonDown -= OnMouseLeftButtonDown;
}
}
}
private static void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
DependencyObject dependencyObject = GetParentFromVisualTree(e.OriginalSource);
if (dependencyObject == null)
{
return;
}
var textBox = (TextBox)dependencyObject;
if (!textBox.IsKeyboardFocusWithin)
{
textBox.Focus();
e.Handled = true;
}
}
private static DependencyObject GetParentFromVisualTree(object source)
{
DependencyObject parent = source as UIElement;
while (parent != null && !(parent is TextBox))
{
parent = VisualTreeHelper.GetParent(parent);
}
return parent;
}
private static void OnKeyboardFocusSelectText(object sender, KeyboardFocusChangedEventArgs e)
{
TextBox textBox = e.OriginalSource as TextBox;
if (textBox != null)
{
textBox.SelectAll();
}
}
[AttachedPropertyBrowsableForChildrenAttribute(IncludeDescendants = false)]
[AttachedPropertyBrowsableForType(typeof(TextBox))]
public static bool GetActive(DependencyObject @object)
{
return (bool) @object.GetValue(ActiveProperty);
}
public static void SetActive(DependencyObject @object, bool value)
{
@object.SetValue(ActiveProperty, value);
}
}
对于我的“一般但不总是”功能，我在(全局)文本框样式中将这个附件属性设置为True。这样，“选择文本”总是“打开”的，但我可以在每个文本框的基础上禁用它。
Donnelle的答案是最好的，但是必须派生一个新的类来使用它是一种痛苦。
我没有这样做，而是在App.xaml.cs中为应用程序中的所有文本框注册处理程序。这允许我使用一个标准的文本框控件唐纳利的答案。
在App.xaml.cs中添加以下方法:
public partial class App : Application
{
protected override void OnStartup(StartupEventArgs e)
{
// Select the text in a TextBox when it receives focus.
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.PreviewMouseLeftButtonDownEvent,
new MouseButtonEventHandler(SelectivelyIgnoreMouseButton));
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.GotKeyboardFocusEvent,
new RoutedEventHandler(SelectAllText));
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.MouseDoubleClickEvent,
new RoutedEventHandler(SelectAllText));
base.OnStartup(e);
}
void SelectivelyIgnoreMouseButton(object sender, MouseButtonEventArgs e)
{
// Find the TextBox
DependencyObject parent = e.OriginalSource as UIElement;
while (parent != null && !(parent is TextBox))
parent = VisualTreeHelper.GetParent(parent);
if (parent != null)
{
var textBox = (TextBox)parent;
if (!textBox.IsKeyboardFocusWithin)
{
// If the text box is not yet focused, give it the focus and
// stop further processing of this click event.
textBox.Focus();
e.Handled = true;
}
}
}
void SelectAllText(object sender, RoutedEventArgs e)
{
var textBox = e.OriginalSource as TextBox;
if (textBox != null)
textBox.SelectAll();
}
}
我们有它，所以第一次点击选择所有，另一次点击光标(我们的应用程序是设计用于平板电脑与笔)。
你可能会发现它很有用。
public class ClickSelectTextBox : TextBox
{
public ClickSelectTextBox()
{
AddHandler(PreviewMouseLeftButtonDownEvent,
new MouseButtonEventHandler(SelectivelyIgnoreMouseButton), true);
AddHandler(GotKeyboardFocusEvent,
new RoutedEventHandler(SelectAllText), true);
AddHandler(MouseDoubleClickEvent,
new RoutedEventHandler(SelectAllText), true);
}
private static void SelectivelyIgnoreMouseButton(object sender,
MouseButtonEventArgs e)
{
// Find the TextBox
DependencyObject parent = e.OriginalSource as UIElement;
while (parent != null && !(parent is TextBox))
parent = VisualTreeHelper.GetParent(parent);
if (parent != null)
{
var textBox = (TextBox)parent;
if (!textBox.IsKeyboardFocusWithin)
{
// If the text box is not yet focussed, give it the focus and
// stop further processing of this click event.
textBox.Focus();
e.Handled = true;
}
}
}
private static void SelectAllText(object sender, RoutedEventArgs e)
{
var textBox = e.OriginalSource as TextBox;
if (textBox != null)
textBox.SelectAll();
}
}
这是迄今为止我找到的最直接的解决方案。
您将只需要几行代码。
向应用程序添加全局处理程序(App.xaml.cs)。
使用EventManager类针对一个类型(在本例中为TextBox)注册一个全局事件处理程序。
protected override void OnStartup(StartupEventArgs e)
{
EventManager.RegisterClassHandler(typeof(TextBox),
TextBox.GotFocusEvent,
new RoutedEventHandler(TextBox_GotFocus));
base.OnStartup(e);
}
然后使用事件处理程序选择所有文本框内容。
private void TextBox_GotFocus(object sender, RoutedEventArgs e)
{
(sender as TextBox).SelectAll();
}
查看这里:WPF文本框选择焦点
我希望这能有所帮助。
