ZedGraph 用图表线平滑移动 Y2Axis

在回答我的问题时“ZedGraph 自定义图表”我有每秒插入数据的图表，现在我有其他问题：

1. 如何用图表线平滑地向下移动Y2轴（DateTime类型）并在图表中始终只显示最后30分钟？

2. 如何格式化 Y2Axis 标签“HH:mm”以获得 10:05、10:10、10:15、...、10:30？

感谢帮助！

UPD1: Thanks kmp! I try your code - its good, but with issue: when I started I see this: When after few minutes I see this picture:

我对图表区域进行了“压缩”，但我希望始终静态显示最后 30 分钟的数据，并缓慢向下移动旧数据，而无需缩放或用轴“包装”图表。我希望你能理解我。

UPD2: Yet another issue - labels of Y2Axis haven't fixed values. For example now:

And after few seconds:

从最简单的开始 - 格式化标签可以像这样完成：

myPane.Y2Axis.Scale.Format = "HH:mm";

您可以执行此操作的一种方法（感觉有点不稳定，但我会让您决定）是在超出阈值（在本例中超过 30 分钟）时简单地将点从曲线中删除。这样，当图表重新绘制时，轴将相应更新。

我觉得采用比例最小值可能是比这更好的方法，但如果失败了，您可以简单地在添加点时维护一个队列，如下所示，然后在它们超出阈值时将其删除：

private Queue<DateTime> axisTimes;

private static readonly Random rnd = new Random();

private void button1_Click(object sender, EventArgs e)
{
    GraphPane myPane = zg1.GraphPane;

    myPane.XAxis.IsVisible = false;

    myPane.X2Axis.IsVisible = true;
    myPane.X2Axis.MajorGrid.IsVisible = true;
    myPane.X2Axis.Scale.Min = 0;
    myPane.X2Axis.Scale.Max = 600;

    myPane.YAxis.IsVisible = false;

    myPane.Y2Axis.IsVisible = true;
    myPane.Y2Axis.Scale.MajorUnit = DateUnit.Minute;
    myPane.Y2Axis.Scale.MinorUnit = DateUnit.Second;
    myPane.Y2Axis.Scale.Format = "HH:mm";
    myPane.Y2Axis.Type = AxisType.DateAsOrdinal;

    LineItem myCurve = myPane.AddCurve("Alpha",
                                  new PointPairList(),
                                  Color.Red,
                                  SymbolType.None);

    myCurve.Symbol.Fill = new Fill(Color.White);
    myCurve.IsX2Axis = true;
    myCurve.IsY2Axis = true;

    myPane.Chart.Fill = new Fill(Color.White, Color.LightGray, 45.0f);
    zg1.IsShowPointValues = true;

    axisTimes = new Queue<DateTime>();

    var t = new System.Windows.Forms.Timer();
    t.Interval = 1000;
    t.Tick += ShowData;

    Thread.Sleep(100);

    t.Start();
}

private void ShowData(object sender, EventArgs e)
{
    var t = (System.Windows.Forms.Timer) sender;
    t.Enabled = false;

    int x = rnd.Next(500, 600);
    var y = new XDate(DateTime.Now);

    var myCurve = zg1.GraphPane.CurveList[0];

    if (axisTimes.Any())
    {             
        // Remove any points that go beyond our time threshold
        while ((((DateTime)y) - axisTimes.Peek()).TotalMinutes > 30)
        {
            myCurve.RemovePoint(0);
            axisTimes.Dequeue();

            if (!axisTimes.Any())
            {
                break;
            }
        }
    }

    // Add the new point and store the datetime that it was added in
    // our own queue
    axisTimes.Enqueue(y);
    myCurve.AddPoint(x, y);

    zg1.AxisChange();
    zg1.Invalidate();

    t.Enabled = true;
}