如何从自动缩放图表控件中获得最大的Y轴值 [英] How to get maximum Y-axis value from autoscaling chart control

问题描述

所以我在.NET中使用图表控制，使用内部自动缩放算法为Y轴。这一切的伟大工程，但我现在想获得Y轴的最大显示值保存为一个双重用于进一步的格式。

So I am using a Chart control in .NET which is using the internal autoscale algorithm for the Y-Axis. This all works great, but I am now trying to get the maximum displayed value of the Y-Axis to store as a double to use for further formatting.

不幸的是，使用ChartControl.ChartAreas [0] .AxisY.Maximum返回do​​uble NaN的，因为我使用的自动缩放。

Unfortunately, using ChartControl.ChartAreas[0].AxisY.Maximum returns the double NaN because I am using autoscale.

是否有可能使用自动缩放轴时，你得到的Y轴的最大显示值？

Is it possible to get the maximum displayed value of the Y-Axis when using an autoscaling axis?

修改 在我执行操作的顺序是建立基本格式为条形图，使用AddXY（加入数据点），最后试图让显示的Y轴的最大值。使用ChartControl.ChartAreas [0] .AxisY.Maximum仍然即使加入大量的数据点返回NaN。

EDIT The order in which I am performing operations is to establish basic formatting for the bar chart, adding datapoints using AddXY(), and then finally trying to get the maximum value of the displayed Y-Axis. Using ChartControl.ChartAreas[0].AxisY.Maximum still returns NaN even after adding numerous datapoints.

推荐答案

这不计算最大值，直至显示图表所以下面code显示楠：

It doesn't compute the max value until the chart is displayed so the following code displays NaN:

public Form1()
{
    InitializeComponent();
    this.chart1.Series.Clear();
    this.chart1.Series.Add("My Data");
    this.chart1.Series[0].Points.AddXY(1, 1);
    this.chart1.Series[0].Points.AddXY(2, 2);
    this.chart1.Series[0].Points.AddXY(3, 6);
    MessageBox.Show(this.chart1.ChartAreas[0].AxisY.Maximum.ToString()); // returns NaN
}

但检查显示图表后，会给出正确的值：

But checking after the chart is displayed will give the correct value:

public Form1()
{
    InitializeComponent();
    this.chart1.Series.Clear();
    this.chart1.Series.Add("My Data");
    this.chart1.Series[0].Points.AddXY(1, 1);
    this.chart1.Series[0].Points.AddXY(2, 2);
    this.chart1.Series[0].Points.AddXY(3, 6);
}

private void button1_Click(object sender, EventArgs e)
{
    MessageBox.Show(this.chart1.ChartAreas[0].AxisY.Maximum.ToString()); // returns 8
}

另外，您可以执行后立即设置你的数据的更新（但由于尚未显示在图表的形式构造这是不行的）：

Alternatively you can perform an update right after you set your data (but this won't work in the form constructor because the chart isn't yet displayed):

private void button1_Click(object sender, EventArgs e)
{
    this.chart1.Series.Clear();
    this.chart1.Series.Add("My Data");
    this.chart1.Series[0].Points.AddXY(1, 1);
    this.chart1.Series[0].Points.AddXY(2, 2);
    this.chart1.Series[0].Points.AddXY(3, 6);
    this.chart1.Update();
    MessageBox.Show(this.chart1.ChartAreas[0].AxisY.Maximum.ToString()); // returns 8
}

下面是另一种方式使用OnShown表事件，并做两个数据系列：

Here's another way to do it using the OnShown Form event and two data series:

public Form1()
{
    InitializeComponent();
    this.chart1.Series.Clear();
    this.chart1.Series.Add("My Data");
    this.chart1.Series[0].Points.AddXY(1, 1);
    this.chart1.Series[0].Points.AddXY(2, 2);
    this.chart1.Series[0].Points.AddXY(3, 6);
    this.chart1.Series.Add("My Data2");
    this.chart1.Series[1].Points.AddXY(1, 1);
    this.chart1.Series[1].Points.AddXY(2, 9);
}

protected override void OnShown(EventArgs e)
{
    base.OnShown(e);
    this.chart1.Update();
    MessageBox.Show(this.chart1.ChartAreas[0].AxisY.Maximum.ToString()); // returns 10
}

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