How to automatically select all text on focus in WPF TextBox?

最新推荐文章于 2025-04-08 14:16:03 发布

kissjob

最新推荐文章于 2025-04-08 14:16:03 发布

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分类专栏： WPF 文章标签： wpf textbox processing object application null

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本文详细探讨了在WPF应用中如何处理焦点问题，特别是在文本框中实现自动选中文本的功能。通过自定义类和事件处理，解决传统方法不可接受的问题，确保用户体验得到提升。

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http://stackoverflow.com/questions/660554/how-to-automatically-select-all-text-on-focus-in-wpf-textbox

Why is focus in WPF so tricky? [managing and understanding focus in a WPF application]

The Basic Idea

Let’s digress first to the Win32 world. In these apps, it’s pretty trivial to do this: handle theWM_GOTFOCUS message, and call ::SendMessage(hWnd, EM_SETSEL, 0, -1).

In Windows Forms, it’s equally simple: handle the control’s GotFocus event and calltextBox.SelectAll().

In WPF, you would think you would just handle the GotFocus event and calltextBox.SelectAll() as well and be done. This will sort of work, but it’s not acceptable.

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();
    }
}