我目前用的头文件：
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

在方法里面怎么写也没有System.Windows.Forms.DataGrid.HitTestInfo这个类！
请教怎么才能用上这个类？

protected void dataGrid1_MouseDown
(object sender, System.Windows.Forms.MouseEventArgs e)
{
Console.WriteLine();
System.Windows.Forms.DataGrid.HitTestInfo myHitTest;
// Use the DataGrid control's HitTest method with the x and y properties.
myHitTest = dataGrid1.HitTest(e.X,e.Y);
Console.WriteLine(myHitTest);
Console.WriteLine("Column " + myHitTest.Column);
Console.WriteLine("Row " + myHitTest.Row);
Console.WriteLine("Type " + myHitTest.Type);
Console.WriteLine("ToString " + myHitTest.ToString());
Console.WriteLine("Hit " + myHitTest.Type.ToString());
}

我这样用无效啊！~~~~

???