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.
这个简单的实现非常适合我:
void TextBox_GotFocus(object sender, RoutedEventArgs e)
{
((TextBox) sender).SelectAll();
}
void TextBox_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
var TextBox = (TextBox) sender;
if (!TextBox.IsKeyboardFocusWithin)
{
TextBox.Focus();
e.Handled = true;
}
}
把它应用到所有的文本框，把下面的代码InitializeComponent();
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.GotFocusEvent, new RoutedEventHandler(TextBox_GotFocus));
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.PreviewMouseDownEvent, new MouseButtonEventHandler(TextBox_PreviewMouseDown));
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();
}
}
我发现这里给出的答案都没有模仿标准的Windows文本框。例如，尝试在文本框的最后一个字符和文本框右侧之间的空白区域单击。这里的大多数解决方案总是选择整个内容，这使得将文本添加到文本框非常困难。
我在这里给出的答案在这方面表现得更好。它是一个行为(因此它需要来自Blend SDK的System.Windows.Interactivity程序集)。也可以使用附加属性重写。
public sealed class SelectAllTextOnFocusBehavior : Behavior<TextBox>
{
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.PreviewMouseLeftButtonDown += AssociatedObject_PreviewMouseLeftButtonDown;
}
protected override void OnDetaching()
{
base.OnDetaching();
AssociatedObject.PreviewMouseLeftButtonDown -= AssociatedObject_PreviewMouseLeftButtonDown;
}
void AssociatedObject_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
// Find the textbox
DependencyObject parent = e.OriginalSource as UIElement;
while (parent != null && !(parent is TextBox))
parent = VisualTreeHelper.GetParent(parent);
var textBox = parent as TextBox;
Debug.Assert(textBox != null);
if (textBox.IsFocused) return;
textBox.SelectAll();
Keyboard.Focus(textBox);
e.Handled = true;
}
}
这是基于我在这里找到的代码。
这个简单的实现非常适合我:
void TextBox_GotFocus(object sender, RoutedEventArgs e)
{
((TextBox) sender).SelectAll();
}
void TextBox_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
var TextBox = (TextBox) sender;
if (!TextBox.IsKeyboardFocusWithin)
{
TextBox.Focus();
e.Handled = true;
}
}
把它应用到所有的文本框，把下面的代码InitializeComponent();
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.GotFocusEvent, new RoutedEventHandler(TextBox_GotFocus));
EventManager.RegisterClassHandler(typeof(TextBox), TextBox.PreviewMouseDownEvent, new MouseButtonEventHandler(TextBox_PreviewMouseDown));
