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.


当前回答

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));

其他回答

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();
}

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);
}

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……

我使用这个代码

  private void txtNav_GotFocus(object sender, RoutedEventArgs e)
            {
                e.Handled = true;
                var c = new DispatcherTimer();
                c.Interval = TimeSpan.FromMilliseconds(100);
                c.Tick += (a1, a2) =>
                {
                    c.IsEnabled = false;
                    txtNav.SelectAll();
                };
                c.IsEnabled = true;
    
            }