ProcessTabKey(true)在windows窗体的keydown事件中未在c#splitcontainer上工

在windows窗体的keydown事件中，我正在尝试使用ProcessTabKey()方法，该方法不适用于c#splitcontainer

    public Form1()
    {
        InitializeComponent();
    }
    private void Form1_Load(object sender, EventArgs e)
    {
        this.BringToFront();
        this.Focus();
        this.KeyPreview = true;
    }
    private void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Enter)
        {
                e.Handled = true;
                this.ProcessTabKey(true);
        }
    }