Я получаю следующее исключение при попытке загрузить мой CartesianChart
Объект не может быть преобразован из DBNULL в другие типы
У меня следующий запрос это возвращает несколько NULL s
Вот мой SQL оператор:
SELECT DATENAME(MONTH, d.OPENED) AS MonthValue,
AVG(CASE WHEN d.ASSGNTO = 'E099255' AND d.REV_CLS = 2 THEN DATEDIFF(day, d.DATERSLVD, d.OPENED)
ELSE 0 END) AS SmallCommercialIndust_avg,
AVG(CASE WHEN d.ASSGNTO = 'E099255' AND d.REV_CLS <> 2 THEN DATEDIFF(day, d.DATERSLVD, d.OPENED)
ELSE 0 END) AS Residential_avg
FROM hb_Disputes d
WHERE YEAR(d.OPENED) = YEAR(GETDATE())
GROUP BY DATENAME(MONTH, d.OPENED)
ORDER BY MIN(d.OPENED);
Вот вывод:
MonthValue SmallCommercialIndust_avg Residential_avg
----------------------------------------------------------
January 0 0
February 0 0
March NULL 0
April 0 0
May 0 NULL
June 0 NULL
July 73 0
August 123 0
September 0 136
October 166 0
November 169 0
December 0 NULL
Вот мой WPF код для загрузки моего CartesianChart:
private void ChartValues()
{
// Defines the variable for differnt lines.
List<double> allValues = new List<double>();
List<double> someValues = new List<double>();
try
{
SqlConnection connection = new SqlConnection("Data Source=WINDOWS-B1AT5HC\\SQLEXPRESS;Initial Catalog=CustomerRelations;Integrated Security=True;");
string selectQuery = ("SELECT DATENAME(MONTH, OPENED) AS MonthValue, SUM(CASE WHEN d .ASSGNTO = 'E099255' AND d .REV_CLS = 2 THEN 1 ELSE 0 END) AS SmallCommercialIndust, AVG(CASE WHEN d .ASSGNTO = 'E099255' AND d.REV_CLS = 2 THEN DATEDIFF(day, d.DATERSLVD, d.OPENED) ELSE 0 END) AS SmallCommercialIndust_avg, SUM(CASE WHEN d.ASSGNTO = 'E099255' AND d.REV_CLS <> 2 THEN 1 ELSE 0 END) AS Residential, AVG(CASE WHEN d.ASSGNTO = 'E099255' AND d.REV_CLS <> 2 THEN DATEDIFF(day, d.DATERSLVD, d.OPENED) ELSE 0 END) AS Residential_avg FROM hb_Disputes AS d WHERE(YEAR(OPENED) = YEAR(GETDATE())) GROUP BY DATENAME(MONTH, OPENED) ORDER BY MIN(OPENED)");
connection.Open();
using SqlCommand command = new SqlCommand(selectQuery, connection);
SqlDataReader sqlReader = command.ExecuteReader();
while (sqlReader.Read())
{
{
// Select the values from the columns selected
allValues.Add(Convert.ToDouble(sqlReader["SmallCommercialIndust_avg"]));
someValues.Add(Convert.ToDouble(sqlReader["Residential_avg"]));
}
// Starts new line series.
SeriesCollection = new SeriesCollection
{
new LineSeries
{
Title = "Residential",
Values = new ChartValues<double>(allValues),
LineSmoothness = 1, //0: straight lines, 1: really smooth lines
},
new LineSeries
{
Title = "Small Commercial Indust",
Values = new ChartValues<double>(someValues),
LineSmoothness = 1, //0: straight lines, 1: really smooth lines
}
};
Labels = new[] { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
YFormatter = value => value.ToString("N");
DataContext = this;
}
connection.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}