实现思路为，在该窗体上添加一个lable标签，当鼠标经过折线点时获取该点的x轴，y轴值和鼠标坐标值。然后将lable的坐标标记为鼠标所在坐标，并且给lable赋值，并且将lable显示出来。
具体实现代码如下：
/// <summary>
/// 鼠标移动到曲线图上显示值
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void chart4_MouseMove(object sender, MouseEventArgs e)
{
var chart = sender as Chart;
if (chart != null)
{
HitTestInfo hit = chart.HitTest(e.X, e.Y);
var o = hit.Object as Element;
if (o != null)
{
var yvaule = o.YValue;
label2.Visible = true;//鼠标经过时label显示
label2.Text = yvaule.ToString(CultureInfo.InvariantCulture);
label2.Location = new Point(e.X, e.Y - 20);
}
else//鼠标离开时lable隐藏
{
label2.Visible = false;
}
}
}
