C# 如何在 System.Windows.Forms.DataVisualization.Charting 的 X 轴上设置 DateTime 范围？
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How do you set DateTime range on X axis for System.Windows.Forms.DataVisualization.Charting?
提问by user8128167
Presently I am attempting to display a chart using windows forms that shows monthly data on the X axis and an integer value on the Y axis; however, I am not setting the range properly for the X Axis, where MonthYear is a DateTime:
目前，我正在尝试使用 Windows 窗体显示图表，该图表在 X 轴上显示每月数据，在 Y 轴上显示一个整数值；但是，我没有为 X 轴正确设置范围，其中 MonthYear 是日期时间：
var pnChart = new System.Windows.Forms.Panel();
pnChart.Controls.Clear();
DataTable dtChartData = myDatabaseLayer.BuildDataTable("SELECT Added, Modified FROM tblStatistics WHERE ApplicationID = " + intApplicationID + " ORDER BY MonthYear");
Chart chart = GenerateChart(dtChartData, pnChart.Width, pnChart.Height, "ActiveBorder", 6);
chart.Series[0].XValueType = ChartValueType.DateTime;
chart.ChartAreas[0].AxisX.LabelStyle.Format = "yyyy-MM-dd";
chart.ChartAreas[0].AxisX.Interval = 1;
chart.ChartAreas[0].AxisX.IntervalType = DateTimeIntervalType.Months;
chart.ChartAreas[0].AxisX.IntervalOffset = 1;
pnChart.Controls.Add(chart);
The problem is, when the chart is displayed, the X axis has the datetime "1900-01-01" so my question is, how do I set the date range to start at 2013-01-01?
问题是，当显示图表时，X 轴的日期时间为“1900-01-01”，所以我的问题是，如何将日期范围设置为从 2013-01-01 开始？
Please note that I have searched the internet and tried the following settings, but they do not give me the correct range:
请注意，我已经在互联网上搜索并尝试了以下设置，但它们没有给我正确的范围：
chart.ChartAreas[0].AxisX.Maximum = DateTime.Now.Ticks;
Or,
或者，
chart.ChartAreas[0].AxisX.Crossing = DateTime.Now.Ticks;
Or,
或者，
chart.ChartAreas[0].AxisX.Minimum = DateTime.Now.Ticks;
TIA.
TIA。
UPDATE:Please note that I found how to set the range properly using this:
更新：请注意，我找到了如何使用此正确设置范围：
chart.Series[0].XValueType = ChartValueType.DateTime;
DateTime minDate = new DateTime(2013, 01, 01);
DateTime maxDate = DateTime.Now;
chart.ChartAreas[0].AxisX.Minimum = minDate.ToOADate();
chart.ChartAreas[0].AxisX.Maximum = maxDate.ToOADate();
The above code sets the proper range now for the X axis; however, now chart itself is blank.
上面的代码现在为 X 轴设置了适当的范围；然而，现在图表本身是空白的。
UPDATE 2:
更新 2：
Yes, thank you DasKrumelmonster--that fixed it! I was using code from http://www.codeproject.com/Articles/168056/Windows-Charting-Application, and simply should have looked more closely at the author's protected internal Chart GenerateChart(DataTable dtChartDataSource, int width, int height, string bgColor, int intType) function. To correct the issue, I changed these lines:
是的，谢谢 DasKrumelmonster——修复它！我正在使用来自http://www.codeproject.com/Articles/168056/Windows-Charting-Application 的代码，只是应该更仔细地查看作者受保护的内部 Chart GenerateChart(DataTable dtChartDataSource, int width, int height, string bgColor, int intType) 函数。为了解决这个问题，我更改了以下几行：
foreach (DataRow dr in dtChartDataSource.Rows)
{
double dataPoint = 0;
double.TryParse(dr[dc.ColumnName].ToString(), out dataPoint);
DataPoint objDataPoint = new DataPoint() { AxisLabel = "series", YValues = new double[] { dataPoint } };
chart.Series[series].Points.Add(dataPoint);
}
To this:
对此：
DateTime dtStart = new DateTime(2013, 01, 01);
int intMonthCounter = 0;
//Add data points to the series
foreach (DataRow dr in dtChartDataSource.Rows)
{
double dataPoint = 0;
double.TryParse(dr[dc.ColumnName].ToString(), out dataPoint);
DataPoint objDataPoint = new DataPoint() { AxisLabel = "series", YValues = new double[] { dataPoint } };
chart.Series[series].Points.AddXY(dtStart.AddMonths(intMonthCounter), dataPoint);
intMonthCounter++;
}
Thank you!
谢谢！
采纳答案by DasKrümelmonster
Cannot reproduce. I tried this code:
无法重现。我试过这个代码：
private void button1_Click(object sender, EventArgs e)
{
var s = new Series();
s.ChartType = SeriesChartType.Line;
var d = new DateTime(2013, 04, 01);
s.Points.AddXY(d, 3);
s.Points.AddXY(d.AddMonths(-1), 2);
s.Points.AddXY(d.AddMonths(-2), 1);
s.Points.AddXY(d.AddMonths(-3), 4);
chart1.Series.Clear();
chart1.Series.Add(s);
chart1.Series[0].XValueType = ChartValueType.DateTime;
chart1.ChartAreas[0].AxisX.LabelStyle.Format = "yyyy-MM-dd";
chart1.ChartAreas[0].AxisX.Interval = 1;
chart1.ChartAreas[0].AxisX.IntervalType = DateTimeIntervalType.Months;
chart1.ChartAreas[0].AxisX.IntervalOffset = 1;
chart1.Series[0].XValueType = ChartValueType.DateTime;
DateTime minDate = new DateTime(2013, 01, 01).AddSeconds(-1);
DateTime maxDate = new DateTime(2013, 05, 01); // or DateTime.Now;
chart1.ChartAreas[0].AxisX.Minimum = minDate.ToOADate();
chart1.ChartAreas[0].AxisX.Maximum = maxDate.ToOADate();
}
Maybe I fixed your error on the way.
也许我在途中修正了你的错误。
It works as expected: One line with four data points, all x-axes labels are visible and so is the graph itself. If there is still an issue, please provide full testing code along with a description of what should happen vs. what actually happens.
它按预期工作：一行包含四个数据点，所有 x 轴标签都是可见的，图形本身也是如此。如果仍然存在问题，请提供完整的测试代码以及应该发生的情况与实际发生的情况的描述。
