ASP.NET Chart not showing line with one day of data, data is present in the series

Question

I have a chart control that works normally for all but one case.

If I select a date range of 1 day, (7/27/2011 to 7/28/2011) or anything greater I see the trend line and can adjust the layout and formatting of the labels accordingly.

If I select one day (7/27/2011 - 7/27/2011) I see the series show up in the legend and the y-axis scales appropriately but no trend line is shown.

Each day has 144 datapoints and when I select one day of data I see 144 points come across if I export data from the chart into an XML file or put up a message box when I am building my series. I see the same results if I select multiple days, with the appropriate amount of days included.

I have datapoints every 10 minutes during each day and if I display a messagebox with the values that are being added to the series I see data when I am looking at the single day range so I assume that I should be seeing a trend line.

What am I missing here?

Here is the code for the chart:

<asp:chart id="Chart1" runat="server" Height="365px" 
      Width="700px" ImageLocation="~/TempImages/ChartPic_#SEQ(300,3)" ImageType="Png" 
      BackColor="WhiteSmoke" BackSecondaryColor="White" BackGradientStyle="TopBottom" 
      palette="BrightPastel" BorderWidth="2" 
      BorderColor="26, 59, 105">
          <titles>
              <asp:Title ShadowColor="32, 0, 0, 0" Font="Trebuchet MS, 14.25pt, style=Bold" ShadowOffset="3" Text="Chart Title" Alignment="MiddleLeft" ForeColor="26, 59, 105"></asp:Title>
          </titles>
      <legends>
          <asp:Legend Enabled="True" IsTextAutoFit="False" Name="Default" BackColor="Transparent" Font="Trebuchet MS, 8.25pt, style=Bold"></asp:Legend>
          </legends>
      <borderskin skinstyle="Emboss"></borderskin>
          <chartareas>
              <asp:ChartArea Name="ChartArea1" BorderColor="64,                                64, 64, 64" BorderDashStyle="Solid" BackSecondaryColor="White" BackColor="Gainsboro" ShadowColor="Transparent" BackGradientStyle="TopBottom">
               <axisy2 enabled="False"></axisy2>
               <axisx2 enabled="False"></axisx2>
                   <area3dstyle Rotation="10" perspective="10"   Inclination="15" IsRightAngleAxes="False" wallwidth="0" IsClustered="False"></area3dstyle>
                   <axisy linecolor="64, 64, 64, 64" IsLabelAutoFit="False" ArrowStyle="Triangle">
                   <labelstyle font="Trebuchet MS, 8.25pt, style=Bold" />
           <majorgrid linecolor="64, 64, 64, 64" />
           </axisy>
           <axisx linecolor="64, 64, 64, 64" IsLabelAutoFit="False" ArrowStyle="Triangle">
                   <labelstyle font="Trebuchet MS, 8.25pt, style=Bold" IsStaggered="False"/>
               <majorgrid linecolor="64, 64, 64, 64" />
        </axisx>
            </asp:ChartArea>
        </chartareas>
    </asp:chart>

And here is the code I am using to build the series:

foreach (TreeNode node in ChartTreeView.CheckedNodes)
{
    if(node.Text.Contains("XXX") )
    {
        Series series = Chart1.Series.Add(node.Text);
        series.ChartArea = "ChartArea1";
        series.ChartType = (SeriesChartType)Enum.Parse(typeof(SeriesChartType), charts[1], true);
        SqlConnection sqlConnection = new SqlConnection(@"DATA GOES HERE FOR SQL");
        sqlConnection.Open();

            SqlCommand nodeQuery = new SqlCommand();
            nodeQuery.CommandText = "";
            if (node.Text.Contains("XXX"))
            {
                nodeQuery.CommandText = "SELECT (Date + CONVERT(datetime,Time)) As TimeStamp, (MW + kW) As Energy, [EquipmentID] FROM EquipmentData WHERE [EquipmentID] = '" + node.Text + "' AND (Date + CONVERT(datetime,Time)) BETWEEN '" + startDateFilter + "' AND '" + endDateFilter + "' and [SiteID] = "+ProjectNavigation.SelectedValue.ToString()+" ORDER BY TimeStamp";";
                nodeQuery.Connection = sqlConnection;

            }
            if (nodeQuery.CommandText != "")
            {
                SqlDataReader reader = nodeQuery.ExecuteReader();
                while (reader.Read())
                {
                    double value = (double)reader["Energy"];
                    DateTime TimeStamp = (DateTime)reader["TimeStamp"];
                    string equipID = (string)reader["EquipmentID"];

                    series.Points.AddXY(TimeStamp, value);

                }
                sqlConnection.Close();
            }
        }
    }
    Chart1.DataBind();

I don't have an interval set in the .aspx file, but I looked through the chart samples provided for the charts and have tried using the following function to set the interval ranges:

public void SetAxisInterval(System.Web.UI.DataVisualization.Charting.Axis axis, double interval, DateTimeIntervalType intervalType)
    {
        SetAxisInterval(axis, interval, intervalType, 0, DateTimeIntervalType.Auto);
    }

    public void SetAxisInterval(System.Web.UI.DataVisualization.Charting.Axis axis, double interval, DateTimeIntervalType intervalType, double intervalOffset, DateTimeIntervalType intervalOffsetType)
    {
        // Set interval-related properties
        axis.Interval = interval;
        axis.IntervalType = intervalType;
        axis.IntervalOffset = intervalOffset;
        axis.IntervalOffsetType = intervalOffsetType;

    }

Calling it with the following for the case where the range of days is 0 days:

SetAxisInterval(Chart1.ChartAreas["ChartArea1"].AxisX, 10, DateTimeIntervalType.Minutes);

A line with one point isn't actually a line, which might be your problem. Try adding an additional dummy point to each series, just as a test. — MatBailie
Please edit in the SQL that you are using instead of "SQL QUERY HERE, IT WORKS CORRECTLY". It may work correctly when you select a span of two days or more, but being able to see how you are filtering the data could be beneficial to getting an answer. — Kyle Trauberman
So, when you select multiple days, are you getting one point per day or 144 points per day (every 10 minutes)? — Narnian
I am seeing 144 data points when I select a single day as verified by displaying a messagebox on each iteration of the loop I am using to add the points to the series and exporting the data to an XML file. — amarcy
After this line: DateTime TimeStamp = (DateTime)reader["TimeStamp"]; is the TimeStamp variable showing the correct parsed date and time? — Kyle Trauberman

amarcy amarcy · Accepted Answer · 2011-08-09T18:31:45

The problem was in setting the minimum and maximum values for the X-axis on the chart.

I had been setting the minimum and maximum to the start and end date which was not displaying data.

DateTime startDateVal;
DateTime endDateVal;

TimeSpan span = DateTime.Parse(endDate.Text) - DateTime.Parse(startDate.Text);
if (span.TotalDays > 0)
{
    startDateVal = DateTime.Parse(startDate.Text);
    endDateVal = DateTime.Parse(endDate.Text;
}
else
{
    startDateVal = DateTime.Parse(startDate.Text);
    endDateVal = DateTime.Parse(endDate.Text).AddDays(1);
}

Chart1.ChartAreas["ChartArea1"].AxisX.Minimum = startDateVal.ToOADate();
Char1t.ChartAreas["ChartArea1"].AxisX.Maximum = endDateVal.ToOADate();

Using the code above to force the maximum to be midnight the day after the currently selected day fixed the problem.

ASP.NET Chart not showing line with one day of data, data is present in the series

1 Answers