问题描述

目前我正在尝试使用 Windows 窗体显示图表，该图表在 X 轴上显示月度数据，在 Y 轴上显示整数值；但是，我没有正确设置 X 轴的范围，其中 MonthYear 是 DateTime:

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:

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);

问题是，当图表显示时，X 轴的日期时间为1900-01-01"所以我的问题是，如何设置日期范围从 2013-01-01 开始?

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?

请注意，我已经搜索了互联网并尝试了以下设置，但它们没有给我正确的范围:

Please note that I have searched the internet and tried the following settings, but they do not give me the correct range:

chart.ChartAreas[0].AxisX.Maximum = DateTime.Now.Ticks;

或者，

chart.ChartAreas[0].AxisX.Crossing = DateTime.Now.Ticks;

或者，

chart.ChartAreas[0].AxisX.Minimum = DateTime.Now.Ticks;

TIA.

更新:请注意，我找到了如何正确设置范围的方法:

UPDATE: Please note that I found how to set the range properly using this:

            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();

上面的代码现在为 X 轴设置了合适的范围；但是，现在图表本身是空白的.

The above code sets the proper range now for the X axis; however, now chart itself is blank.

更新 2:

是的，谢谢 DasKrumelmonster - 解决了它！我使用的代码来自 http://www.codeproject.com/Articles/168056/Windows-Charting-Application，应该更仔细地查看作者受保护的内部图表 GenerateChart(DataTable dtChartDataSource, int width, int height, string bgColor, int intType) 函数.为了纠正这个问题，我更改了以下几行:

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:

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);
}

到这里:

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++;
}

谢谢！

推荐答案

无法重现.我试过这段代码:

Cannot reproduce. I tried this code:

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.Add(new ChartArea()); // In some cases the winforms designer adds this already
    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();
}

也许我在途中修正了你的错误.

Maybe I fixed your error on the way.

它按预期工作:一行有四个数据点，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.

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.

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