我有一个这样的应用：
使用图表下方的文本框,用户可以设置图表的X轴的最小值和最大值.这是它的代码：
private void textBoxXaxisMin_TextChanged(object sender,EventArgs e) { double x; //checks if the input is a double and smaller than the max value //if (Double.TryParse(this.textBoxXaxisMin.Text,out x) && x < chart1.ChartAreas[0].AxisX.Maximum) if (Double.TryParse(this.textBoxXaxisMin.Text,out x)) { this.textBoxXaxisMin.BackColor = Color.White; chart1.ChartAreas[0].AxisX.Minimum = Convert.ToDouble(this.textBoxXaxisMin.Text); //changeYScalaMin(chartCharacteristicCurvesThermoelemts,Convert.ToDouble(this.textBoxCharacteristicCurvesThermoelementXmin.Text),Convert.ToDouble(this.textBoxCharacteristicCurvesThermoelementXmax.Text)); //method to scale y axis } else //if the textBox is not highlighted this.textBoxXaxisMin.BackColor = Color.Orange; //calls the Max Function to update the chart if the Max-value is now valid double y; //checks if the input is a double and greater than the min value if (Double.TryParse(this.textBoxXaxisMax.Text,out y) && y > chart1.ChartAreas[0].AxisX.Minimum) { this.textBoxXaxisMax.BackColor = Color.White; chart1.ChartAreas[0].AxisX.Maximum = Convert.ToDouble(this.textBoxXaxisMax.Text); //method to scale y axis } else //if the textBox is not highlighted this.textBoxXaxisMax.BackColor = Color.Orange; }
现在我想让Y轴自动缩放.应将Y-min计算为(X-min和X-max)部分中所有系列的最小值,并将Y-max计算为所选部分中所有系列的最大值.我的问题是实施.
在此示例中,Y-min应更改为大约50.
我在GitHup处主持了这个漏洞示例项目.
解决方法
对于从0到1的所有系列,这会将Y轴缩放到X轴的最小值和最大值[0]之间的最小值和最大值：
double max = Double.MinValue;
double min = Double.MaxValue;
double leftLimit = chart1.ChartAreas[0].AxisX.Minimum;
double rightLimit = chart1.ChartAreas[0].AxisX.Maximum;
for (int s = 0; s <= 1; s++)
{
foreach (DataPoint dp in chart1.Series[s].Points)
{
if (dp.XValue >= leftLimit && dp.XValue <= rightLimit)
{
min = Math.Min(min,dp.YValues[0]);
max = Math.Max(max,dp.YValues[0]);
}
}
}
chart1.ChartAreas[0].AxisY.Maximum = max;
chart1.ChartAreas[0].AxisY.Minimum = min;
编辑：测试时我注意到重置最小值和最大值并不是很明显.方法如下：
chart1.ChartAreas[0].AxisY.Minimum = Double.NaN; chart1.ChartAreas[0].AxisY.Maximum = Double.NaN; chart1.ChartAreas[0].AxisX.Minimum = Double.NaN; chart1.ChartAreas[0].AxisX.Maximum = Double.NaN;
