C#中根据左右上下键控制不多个控件的焦点

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
//定义一个二位数组  存放TextBox控件
TextBox[，] arr;
private void Form1_Load(object sender， EventArgs e)
{
//初始化数组
arr = new TextBox[3， 3]{{textBox1，textBox2，textBox3}，
{textBox4，textBox5，textBox6}，
{textBox7，textBox8，textBox9}
};
}
/// <summary>
/// 窗体键盘事件   注： 启用此事件之前 先设置KeyPreView属性为True
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Form1_KeyDown(object sender， KeyEventArgs e)
{
//首先获取当前焦点的控件
TextBox txt = (TextBox)GetFocusedControl();
//获取当前焦点控件的在数组中对应的位置  此值事先存放在控件的Tag属性中
int x = int.Parse(txt.Tag.ToString().Substring(0， 1));
int y = int.Parse(txt.Tag.ToString().Substring(1， 1));
if (e.KeyCode == Keys.Left)
{
if (y > 0)
{
arr[x， y-1].Focus();
}
}
else if (e.KeyCode == Keys.Right)
{
if (y < 2)
{
arr[x，y + 1].Focus();
}
}
else if (e.KeyCode == Keys.Up)
{
if (x > 0)
{
arr[x-1， y].Focus();
}
}
else if (e.KeyCode == Keys.Down)
{
if (x < 2)
{
arr[x+1， y].Focus();
}
}
}
// DLL调用注册
[DllImport("user32.dll"， CharSet = CharSet.Auto， CallingConvention = CallingConvention.Winapi)]
private static extern IntPtr GetFocus();
/// <summary>
/// 当前拥有焦点的控件
/// </summary>
/// <param name="formControl"></param>
/// <returns></returns>
public static Control GetFocusedControl()
{
Control focusedControl = null;
try
{
IntPtr focusedHandle = GetFocus();
if (focusedHandle != IntPtr.Zero)
{
focusedControl = Control.FromChildHandle(focusedHandle);
}
}
catch { }
return focusedControl;
}
}