/// <summary>
/// 定义自动滚动定位委托
/// </summary>
/// <param name="ctrl">指定的自动滚动定位的控件</param>
/// <param name="p">指定的自动滚动定位的位置</param>
protected delegate void AutoScrollPositionDelegate(ScrollableControl ctrl, Point p);
private void TextBox1_Enter(EventArgs e)
{
    if (Parent is Panel)
    {
        Point p = (this.Parent as Panel).AutoScrollPosition;
        AutoScrollPositionDelegate del = new AutoScrollPositionDelegate(SetAutoScrollPosition);
        Object[] args = { this.Parent as Panel, p};
        BeginInvoke(del, args);
    }
}
/// <summary>
/// 设置指定的可滚动控件的自动滚动定位的位置。
/// </summary>
/// <param name="sender"></param>
/// <param name="p"></param>
private void SetAutoScrollPosition(ScrollableControl sender, Point p)
{
    p.X = Math.Abs(p.X);
    p.Y = Math.Abs(p.Y);
    sender.AutoScrollPosition = p;
}

Panel.AutoScrollPosition：获取或设置自动滚动定位的位置。需注意，设置的时候X，Y得为正数；获取的却是负数。