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();
    }
}

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;
    
            }

如果有一个事件，取消选择的文本在OnFocus鼠标向上，我通常只是延迟全部选择。

private void TextBox_GotFocus(object sender, RoutedEventArgs e)
{
    if (TextBox.Text != null)
    {
        _ = Task.Run(() =>
        {
            Dispatcher.Invoke(
                async () => {
                    await Task.Delay(100);
                    TextBox.SelectAll();
                }
            );
        });
    }
}

我以为这样简单多了。

nameOfTextbox.Focus();
nameOfTextbox.Select(0, nameOfTextbox.Text.Length);

同样，如果别人有你的光标不聚焦在文本框的问题，你可以使用这个在nameOfTextbox.Focus();以上。

Dispatcher.BeginInvoke(DispatcherPriority.Input,
new Action(delegate () {
    nameOfTextbox.Focus();         // Set Logical Focus
    Keyboard.Focus(nameOfTextbox); // Set Keyboard Focus
}));

我已经测试了所有的，但只有以下工作:

protected override void OnStartup(StartupEventArgs e) 
{
    EventManager.RegisterClassHandler(typeof(TextBox), UIElement.PreviewMouseLeftButtonDownEvent,
   new MouseButtonEventHandler(SelectivelyHandleMouseButton), true);
    EventManager.RegisterClassHandler(typeof(TextBox), UIElement.GotKeyboardFocusEvent,
      new RoutedEventHandler(SelectAllText), true);
    EventManager.RegisterClassHandler(typeof(TextBox), UIElement.GotFocusEvent,
      new RoutedEventHandler(GotFocus), true);          
}

private static void SelectivelyHandleMouseButton(object sender, MouseButtonEventArgs e)
{
    var textbox = (sender as TextBox);
    if (textbox != null)
    {
        int hc = textbox.GetHashCode();
        if (hc == LastHashCode)
        {
            if (e.OriginalSource.GetType().Name == "TextBoxView")
            {
                e.Handled = true;
                textbox.Focus();
                LastHashCode = -1;
            }
        }
    }
    if (textbox != null) textbox.Focus();
}

private static void SelectAllText(object sender, RoutedEventArgs e)
{
    var textBox = e.OriginalSource as TextBox;
    if (textBox != null)
        textBox.SelectAll();
}

private static int LastHashCode;
private static void GotFocus(object sender, RoutedEventArgs e)
{
    var textBox = e.OriginalSource as TextBox;
    if (textBox != null)
        LastHashCode = textBox.GetHashCode();
}