如何查看最近10次数据点在图表中多数民众赞成在更新每一秒？ [英] How to view the last 10 DataPoints in a chart that's updating each second?

问题描述

我有这个code：

private void timer_Tick(object sender, EventArgs e)
    {
        timer.Stop();
        for (int i = 0; i < TOTAL_SENSORS; i++)
        {
            DateTime d = DateTime.Now;
            devices[i].Value = float.Parse(serialPort.ReadLine());
            if (chart1.Series[i].Points.Count > MAX_POINTS)
            {
                //see the most recent points
            }
            chart1.Series[i].Points.AddXY(d, devices[i].Value);
        }
        timer.Start();
    }

我的code这部分是计时器的Tick事件在那里我画一个图，我需要更新它的每tick.I不断增加点，当点计数达到MAX_POINTS（10），它消除了第一点和添加了一个新的结尾。

This part of my code is the timer's tick event where i draw a chart and i need to update it every tick.I keep adding points and when the points count reaches MAX_POINTS(10) it removes the first point and adds a new one at the end.

的问题是，当它到达MAX_POINTS它开始除去点的端部和图形不自动滚动。所有点都被删除，并没有新的点得到补充。

The problem is when it reaches MAX_POINTS it starts removing points at the end and the graph doesn't autoscroll. All points get deleted and no new points get added.

请帮助我，说什么我需要更改图表工作，我说。

Please help me and say what I need to change the chart to work as I said.

编辑1：我使用Windows窗体

EDIT 1: I am using Windows Forms.

编辑2：AddXY和RemoveAt不是我的，他们都是从点集合

EDIT 2: AddXY and RemoveAt are not mine they are from the points collection.

编辑3：我也想知道如何拥有一个范围，并看到数据的最后一小时，或在过去的一周上个月

EDIT 3: I also want to know how to have a 'scope' and see the data for the last hour or for the last week or for the last month.

编辑4：我改变了我的问题了一下，我现在要缩放的图表，从最后一个小时/天，显示点

推荐答案

存储在单独的字典中的点和图表。然后，你可以查询字典，当你想要的最新点。

Store the points in a separate dictionary as well as the chart. Then you can just query the dictionary when you want the most recent points.

Dictionary<DateTime, float> points = new Dictionary<DateTime, float>();

然后直接您的来电后，加入这行 AddXY（）：

points.Add(d, devices[i].Value);

如果你想保持字典同步的图表，从词典中删除的第一个元素以及

and if you want to keep the dictionary in sync with the chart, remove the first element from the dictionary as well:

points.Remove(points.Keys[0]);

---

要查询的字典，你可以使用LINQ：取（）文档的跳过（）文档

IEnumerable<KeyValuePair<DateTime, float>> mostRecent = points.Skip(points.Count - 10).Take(10);

或者你可以得到一个特定的点（假设你想从一分钟前的点）

or you can get a specific point (lets say you want the point from one minute ago)

float value = points[DateTime.Now.AddMinutes(-1)];

或者你可以遍历所有的项目：

or you can loop over the items:

foreach(KeyValuePair<DateTime, float> point in points)
{
    DateTime time = point.Key;
    float value = point.Value;
}

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