C# winform中chart使用tooltip显示Y轴坐标

Question

在一个chart中同时显示了很多曲线，我设置了一个X轴游标，跟随鼠标移动的，我想添加一个TOOLTIP来显示Y轴的坐标，问题就是要抓到最近的那条曲线上去显示Y轴的值，尝试了几次一直显示的是鼠标的Y轴的值，该怎么处理呢？

        private void chart1_MouseMove(object sender, MouseEventArgs e)
        {
            Point point = new Point(e.X, e.Y);
            chart1.ChartAreas[0].CursorX.SetCursorPixelPosition(point, true);//X轴游标跟随移动
        }

@CSDN专家-showbo

Answer 1

改下面就行，效果如下

        private void chart1_MouseMove(object sender, MouseEventArgs e)
        {
            Point point = new Point(e.X, e.Y);
            chart1.ChartAreas[0].CursorX.SetCursorPixelPosition(point, true);//X轴游标跟随移动

            if (chart1.Series.Count == 0) return;
            var x = (int)chart1.ChartAreas[0].CursorX.Position;
            if (x < 0 || x >= chart1.Series[0].Points.Count) return;

            var builder = new StringBuilder();
            builder.AppendLine("X轴：" + chart1.Series[0].Points[x].AxisLabel);

            foreach (var s in chart1.Series) builder.AppendLine(s.Name + "Y轴：" + Math.Round(s.Points[x].YValues[0], 2));
       
            chart1.ShowTooltip(toolTip1, builder.ToString(), 4, 3, 10000);

        }

注意添加扩展类及往winform中添加tooltip控件

    public static class CToolTip
    {
        /// <summary>
        /// 为控件提供Tooltip
        /// </summary>
        /// <param name="control">控件</param>
        /// <param name="tip">ToolTip</param>
        /// <param name="message">提示消息</param>
        public static void ShowTooltip(this Control control, ToolTip tip, string message)
        {
            Point _mousePoint = Control.MousePosition;
            int _x = control.PointToClient(_mousePoint).X;
            int _y = control.PointToClient(_mousePoint).Y;
            tip.Show(message, control, _x, _y);
            tip.Active = true;
        }
        /// <summary>
        /// 为控件提供Tooltip
        /// </summary>
        /// <param name="control">控件</param>
        /// <param name="tip">ToolTip</param>
        /// <param name="message">提示消息</param>
        /// <param name="durationTime">保持提示的持续时间</param>
        public static void ShowTooltip(this Control control, ToolTip tip, string message, int durationTime)
        {
            Point _mousePoint = Control.MousePosition;
            int _x = control.PointToClient(_mousePoint).X;
            int _y = control.PointToClient(_mousePoint).Y;
            tip.Show(message, control, _x, _y, durationTime);
            tip.Active = true;
        }
        /// <summary>
        /// 为控件提供Tooltip
        /// </summary>
        /// <param name="control">控件</param>
        /// <param name="tip">ToolTip</param>
        /// <param name="message">提示消息</param>
        /// <param name="xoffset">水平偏移量</param>
        /// <param name="yoffset">垂直偏移量</param>
        public static void ShowTooltip(this Control control, ToolTip tip, string message, int xoffset, int yoffset)
        {
            Point _mousePoint = Control.MousePosition;
            int _x = control.PointToClient(_mousePoint).X;
            int _y = control.PointToClient(_mousePoint).Y;
            tip.Show(message, control, _x + xoffset, _y + yoffset);
            tip.Active = true;
        }
        /// <summary>
        /// 为控件提供Tooltip
        /// </summary>
        /// <param name="control">控件</param>
        /// <param name="tip">ToolTip</param>
        /// <param name="message">提示消息</param>
        /// <param name="xoffset">水平偏移量</param>
        /// <param name="yoffset">垂直偏移量</param>
        /// <param name="durationTime">保持提示的持续时间</param>
        public static void ShowTooltip(this Control control, ToolTip tip, string message, int xoffset, int yoffset, int durationTime)
        {
            Point _mousePoint = Control.MousePosition;
            int _x = control.PointToClient(_mousePoint).X;
            int _y = control.PointToClient(_mousePoint).Y;
            tip.Show(message, control, _x + xoffset, _y + yoffset, durationTime);
            tip.Active = true;
        }
    }

参考：

C# chart图表的简单使用+Tooltip的信息提示_C#Code- Sheep的博客-CSDN博客_c# chart tooltip //设置图表轴箭头形状 chart1.ChartAreas[0].AxisX.ArrowStyle = AxisArrowStyle.Triangle; chart1.ChartAreas[0].AxisY.ArrowStyle = AxisArrowStyle.Triangle;//点击点提示线 chart1.ChartAreas[0].CursorX.IsUserEnabled = true;//用户缩放 . https://blog.csdn.net/weixin_39448579/article/details/120543053