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.
我知道这是非常古老的，但这是我的解决方案，它是基于表达式/微软交互性和交互名称空间。
首先，我按照此链接中的说明将交互性触发器放入样式中。
然后就归结为这个
<Style x:Key="baseTextBox" TargetType="TextBox">
<Setter Property="gint:InteractivityItems.Template">
<Setter.Value>
<gint:InteractivityTemplate>
<gint:InteractivityItems>
<gint:InteractivityItems.Triggers>
<i:EventTrigger EventName="GotKeyboardFocus">
<ei:CallMethodAction MethodName="SelectAll"/>
</i:EventTrigger>
<i:EventTrigger EventName="PreviewMouseLeftButtonDown">
<ei:CallMethodAction MethodName="TextBox_PreviewMouseLeftButtonDown"
TargetObject="{Binding ElementName=HostElementName}"/>
</i:EventTrigger>
</gint:InteractivityItems.Triggers>
</gint:InteractivityItems>
</gint:InteractivityTemplate>
</Setter.Value>
</Setter>
</Style>
这
public void TextBox_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
TextBox tb = e.Source as TextBox;
if((tb != null) && (tb.IsKeyboardFocusWithin == false))
{
tb.Focus();
e.Handled = true;
}
}
在我的例子中，我有一个用户控件，其中的文本框有一个隐藏代码。隐藏代码具有处理程序函数。我在XAML中为用户控件设置了一个名称，并将该名称用于元素。这对我来说非常有效。简单地应用样式的任何文本框，你想有所有的文本选择时，点击在文本框。
当TextBox上的GotKeyboardFocus事件触发时，第一个CallMethodAction调用文本框的SelectAll方法。
我希望这能有所帮助。
我认为这很有效:
private void ValueText_GotFocus(object sender, RoutedEventArgs e)
{
TextBox tb = (TextBox)e.OriginalSource;
tb.Dispatcher.BeginInvoke(
new Action(delegate
{
tb.SelectAll();
}), System.Windows.Threading.DispatcherPriority.Input);
}
如果你想实现它作为一个扩展方法:
public static void SelectAllText(this System.Windows.Controls.TextBox tb)
{
tb.Dispatcher.BeginInvoke(
new Action(delegate
{
tb.SelectAll();
}), System.Windows.Threading.DispatcherPriority.Input);
}
在GotFocus事件中:
private void ValueText_GotFocus(object sender, RoutedEventArgs e)
{
TextBox tb = (TextBox)e.OriginalSource;
tb.SelectAllText();
}
我发现上面的解决方案是因为几个月前我正在寻找一种方法来将焦点设置到给定的UIElement上。我在某处发现了下面的代码(特此给予)，它工作得很好。尽管它与OP的问题没有直接关系，但我还是发布了它，因为它演示了使用Dispatcher处理UIElement的相同模式。
// Sets focus to uiElement
public static void DelayedFocus(this UIElement uiElement)
{
uiElement.Dispatcher.BeginInvoke(
new Action(delegate
{
uiElement.Focusable = true;
uiElement.Focus();
Keyboard.Focus(uiElement);
}),
DispatcherPriority.Render);
}
下面是为方便您实现答案解决方案的Blend行为:
一个用于附加到单个文本框:
public class SelectAllTextOnFocusBehavior : Behavior<TextBox>
{
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.GotKeyboardFocus += AssociatedObjectGotKeyboardFocus;
AssociatedObject.GotMouseCapture += AssociatedObjectGotMouseCapture;
AssociatedObject.PreviewMouseLeftButtonDown += AssociatedObjectPreviewMouseLeftButtonDown;
}
protected override void OnDetaching()
{
base.OnDetaching();
AssociatedObject.GotKeyboardFocus -= AssociatedObjectGotKeyboardFocus;
AssociatedObject.GotMouseCapture -= AssociatedObjectGotMouseCapture;
AssociatedObject.PreviewMouseLeftButtonDown -= AssociatedObjectPreviewMouseLeftButtonDown;
}
private void AssociatedObjectGotKeyboardFocus(object sender,
System.Windows.Input.KeyboardFocusChangedEventArgs e)
{
AssociatedObject.SelectAll();
}
private void AssociatedObjectGotMouseCapture(object sender,
System.Windows.Input.MouseEventArgs e)
{
AssociatedObject.SelectAll();
}
private void AssociatedObjectPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if(!AssociatedObject.IsKeyboardFocusWithin)
{
AssociatedObject.Focus();
e.Handled = true;
}
}
}
一个用于附加到包含多个文本框的容器的根:
public class SelectAllTextOnFocusMultiBehavior : Behavior<UIElement>
{
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.GotKeyboardFocus += HandleKeyboardFocus;
AssociatedObject.GotMouseCapture += HandleMouseCapture;
}
protected override void OnDetaching()
{
base.OnDetaching();
AssociatedObject.GotKeyboardFocus -= HandleKeyboardFocus;
AssociatedObject.GotMouseCapture -= HandleMouseCapture;
}
private static void HandleKeyboardFocus(object sender,
System.Windows.Input.KeyboardFocusChangedEventArgs e)
{
var txt = e.NewFocus as TextBox;
if (txt != null)
txt.SelectAll();
}
private static void HandleMouseCapture(object sender,
System.Windows.Input.MouseEventArgs e)
{
var txt = e.OriginalSource as TextBox;
if (txt != null)
txt.SelectAll();
}
}
哇!读完以上所有内容后，我发现自己不知所措。我从这篇文章中学到了一些东西，并尝试了一些完全不同的东西。当文本框获得焦点时，我使用这个来选择文本:
private void TextField_GotFocus(object sender, RoutedEventArgs e)
{
TextBox tb = (sender as Textbox);
if(tb != null)
{
e.Handled = true;
tb.Focus();
tb.SelectAll();
}
}
将文本框的GotFocus属性设置为该方法。
运行应用程序并在文本框中单击一次，将突出显示文本框中已经存在的所有内容。
如果目标确实是在用户单击文本框时选择文本，这看起来很简单，涉及的代码也少了很多。只是说……
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();
}
}
