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

尝试这个扩展方法,添加所需的行为到任何文本框控件。我还没有对它进行广泛测试,但它似乎满足了我的需求。

public static class TextBoxExtensions
{
    public static void SetupSelectAllOnGotFocus(this TextBox source)
    {
        source.GotFocus += SelectAll;
        source.PreviewMouseLeftButtonDown += SelectivelyIgnoreMouseButton;
    }

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

    private static void SelectivelyIgnoreMouseButton(object sender, MouseButtonEventArgs e)
    {
        var textBox = (sender as TextBox);
        if (textBox != null)
        {
            if (!textBox.IsKeyboardFocusWithin)
            {
                e.Handled = true;
                textBox.Focus();
            }
        }
    }
}

其他回答

不知道为什么它在GotFocus事件中失去了选择。

但是一个解决方案是在GotKeyboardFocus和GotMouseCapture事件上进行选择。这样它就能一直工作。

——编辑——

在这里添加一个例子来告诉人们如何解决上面提到的一些缺点:

private void TextBox_GotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
    // Fixes issue when clicking cut/copy/paste in context menu
    if (textBox.SelectionLength == 0) 
        textBox.SelectAll();
}

private void TextBox_LostMouseCapture(object sender, MouseEventArgs e)
{
    // If user highlights some text, don't override it
    if (textBox.SelectionLength == 0) 
        textBox.SelectAll();

    // further clicks will not select all
    textBox.LostMouseCapture -= TextBox_LostMouseCapture; 
}

private void TextBox_LostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
    // once we've left the TextBox, return the select all behavior
    textBox.LostMouseCapture += TextBox_LostMouseCapture;
}
#region TextBoxIDCard selection
private bool textBoxIDCardGotFocus = false;
private void TextBoxIDCard_GotFocus(object sender, RoutedEventArgs e)
{
    this.TextBoxIDCard.SelectAll();
}

private void TextBoxIDCard_LostFocus(object sender, RoutedEventArgs e)
{
    textBoxIDCardGotFocus = false;
}

private void TextBoxIDCard_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
    if (textBoxIDCardGotFocus == false)
    {
        e.Handled = true;
        this.TextBoxIDCard.Focus();
        textBoxIDCardGotFocus = true;
    }
} 
#endregion

试着把这个放在你的文本框的任何控件的构造函数中:

Loaded += (sender, e) =>
{
    MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
    myTextBox.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。

这是迄今为止我找到的最直接的解决方案。

您将只需要几行代码。

向应用程序添加全局处理程序(App.xaml.cs)。 使用EventManager类针对一个类型(在本例中为TextBox)注册一个全局事件处理程序。

protected override void OnStartup(StartupEventArgs e)
{
    EventManager.RegisterClassHandler(typeof(TextBox),
        TextBox.GotFocusEvent,
        new RoutedEventHandler(TextBox_GotFocus));

    base.OnStartup(e);
}

然后使用事件处理程序选择所有文本框内容。

private void TextBox_GotFocus(object sender, RoutedEventArgs e)
{
    (sender as TextBox).SelectAll();
}

查看这里:WPF文本框选择焦点

我希望这能有所帮助。