重写Windows基类，自定义WPF窗口，实现改回车键为TAB

在WinForm时，可以定义一个基类继承自Form，从而在基类中重写和添加功能，要在WPF中实现类似方法要分为三步：

１.　自定义一个基类MyWindow继承自Window.

2.　 将窗口的CS继承自MyWindow。

3.　在XAML中引用MyWindow命名空间，并在使用其别名自定义WPF窗口。

如下例重写Windows基类，自定义WPF窗口，实现改回车键为TAB：

<DecorationMS:DMSbase x:Class="DecorationMS.MainWindow"
        xmlns:DecorationMS="clr-namespace:DecorationMS.WindowsBase" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="TEST" Height="700" Width="1000">
    <Grid Name="MainGrid">
      
    </Grid>
</DecorationMS:DMSbase>

    public partial class MainWindow : WindowsBase.DMSbase
    {
        public MainWindow()
        {
            InitializeComponent(); 

        }
     }

using System.Windows;
using System.Windows.Input;

namespace DecorationMS.WindowsBase
{
   public class DMSbase : Window
    {
        protected override void OnKeyDown(KeyEventArgs e)
        {
            if (e.Key == Key.Enter)
            {
                // MoveFocus takes a TraveralReqest as its argument. 
                TraversalRequest request = new TraversalRequest(FocusNavigationDirection.Next);

                // Gets the element with keyboard focus. 
                UIElement elementWithFocus = Keyboard.FocusedElement as UIElement;

                // Change keyboard focus. 
                if (elementWithFocus != null)
                {
                    elementWithFocus.MoveFocus(request);
                }
                e.Handled = true;
            }
            base.OnKeyDown(e);
        } 


    }
}