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.
这对我来说似乎很有效。它基本上是一些早期帖子的重述。我只是把它放到构造函数的MainWindow.xaml.cs文件中。我创建了两个处理程序，一个用于键盘，一个用于鼠标，并将两个事件导入同一个函数HandleGotFocusEvent，该函数定义在同一个文件的构造函数之后。
public MainWindow()
{
InitializeComponent();
EventManager.RegisterClassHandler(typeof(TextBox),
UIElement.GotKeyboardFocusEvent,
new RoutedEventHandler(HandleGotFocusEvent), true);
EventManager.RegisterClassHandler(typeof(TextBox),
UIElement.GotMouseCaptureEvent,
new RoutedEventHandler(HandleGotFocusEvent), true);
}
private void HandleGotFocusEvent(object sender, RoutedEventArgs e)
{
if (sender is TextBox)
(sender as TextBox).SelectAll();
}
从这里开始:
在App.xaml.cs文件中注册全局事件处理程序:
protected override void OnStartup(StartupEventArgs e)
{
EventManager.RegisterClassHandler(typeof(TextBox),TextBox.GotFocusEvent,
new RoutedEventHandler(TextBox_GotFocus));
base.OnStartup(e);
}
那么处理程序就像这样简单:
private void TextBox_GotFocus(object sender, RoutedEventArgs e)
{
(sender as TextBox).SelectAll();
}
我用附加行为解决了这个问题，而不是谢尔盖回答中的表达式行为。这意味着我不需要依赖Blend SDK中的System.Windows.Interactivity:
public class TextBoxBehavior
{
public static bool GetSelectAllTextOnFocus(TextBox textBox)
{
return (bool)textBox.GetValue(SelectAllTextOnFocusProperty);
}
public static void SetSelectAllTextOnFocus(TextBox textBox, bool value)
{
textBox.SetValue(SelectAllTextOnFocusProperty, value);
}
public static readonly DependencyProperty SelectAllTextOnFocusProperty =
DependencyProperty.RegisterAttached(
"SelectAllTextOnFocus",
typeof (bool),
typeof (TextBoxBehavior),
new UIPropertyMetadata(false, OnSelectAllTextOnFocusChanged));
private static void OnSelectAllTextOnFocusChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var textBox = d as TextBox;
if (textBox == null) return;
if (e.NewValue is bool == false) return;
if ((bool) e.NewValue)
{
textBox.GotFocus += SelectAll;
textBox.PreviewMouseDown += IgnoreMouseButton;
}
else
{
textBox.GotFocus -= SelectAll;
textBox.PreviewMouseDown -= IgnoreMouseButton;
}
}
private static void SelectAll(object sender, RoutedEventArgs e)
{
var textBox = e.OriginalSource as TextBox;
if (textBox == null) return;
textBox.SelectAll();
}
private static void IgnoreMouseButton(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
var textBox = sender as TextBox;
if (textBox == null || (!textBox.IsReadOnly && textBox.IsKeyboardFocusWithin)) return;
e.Handled = true;
textBox.Focus();
}
}
然后你可以像这样在XAML中使用它:
<TextBox Text="Some Text" behaviors:TextBoxBehavior.SelectAllTextOnFocus="True"/>
我在这里写过博客。
