WPF TextBox 獲得焦點后，文本框中的文字全選中

textbox.GotFocus 事件處理 Textbox.SelectAll() 是不行的, 這樣處理會發生的情況是:
1) textbox1 當前沒有焦點, 內容為 someText.
2) 鼠標點擊 textbox1, 若單擊點位於 someText 之內, 則 someText 被瞬間全選后所有的選擇都被取消, 若單擊點位於 someText 之外, 則不會發生任何事情, 沒有任何選中的內容.

 

如下是解決辦法

 

public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            LIKE_textBox.PreviewMouseDown += new MouseButtonEventHandler(LIKE_textBox_PreviewMouseDown);//注意，這個事件的注冊必須在LIKE_textBox獲得焦點之前
            LIKE_textBox.GotFocus += new RoutedEventHandler(LIKE_textBox_GotFocus);
            LIKE_textBox.LostFocus += new RoutedEventHandler(LIKE_textBox_LostFocus);
        }
 
        void LIKE_textBox_LostFocus(object sender, RoutedEventArgs e)
        {
            LIKE_textBox.PreviewMouseDown += new MouseButtonEventHandler(LIKE_textBox_PreviewMouseDown);
        }
 
        void LIKE_textBox_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            LIKE_textBox.Focus();
            e.Handled = true;
        }
 
        void LIKE_textBox_GotFocus(object sender, RoutedEventArgs e)
        {
            LIKE_textBox.SelectAll();
            LIKE_textBox.PreviewMouseDown -= new MouseButtonEventHandler(LIKE_textBox_PreviewMouseDown);
        }
    }