首先需要在視窗建構函式中為SizeChanged繫結處理事件：

public MainWindow()
        {
            InitializeComponent();
            this.SizeChanged += new System.Windows.SizeChangedEventHandler(MainWindow_Resize);             
        }

 private void MainWindow_Resize(object sender, System.EventArgs e)
        {
            if (this.WindowState == WindowState.Maximized)
            {
                this.exchangeTab.Width = this.Width;
            }
            
        }