Custom Aggregate Function: AggSumIf()

Review the documentation on Custom Aggregate Functions for full details on developing and implementing this function.

Description	Returns the sum of values of `dataToAggregate` with a corresponding true`condition`. Only those records with a true`condition` are included in the sum. `condition` is true if it meets any one of the following conditions: it is the Boolean type `true` it is the string “true“ it is the function `True()` it is a non-zero number, or can be converted to a non-zero number
Arguments	`dataToAggregate`: the data field to sum, accepts data fields or cell references. Required. `condition`: a Boolean value or expression that when true will include this item in the sum. Required. `recordLevel`: indicates whether to aggregate by recordLevel (true) or entity level (false). Optional, defaults true if not provided.
Namespaces	WebReports.Api.Common WebReports.Api.Custom
Example	To return the total number of products ordered in quarter 4: `AggSumIf({OrderDetails.Quantity}, If(QuarterNumber({Orders.OrderDate})=4))` 255

Program Code

public class AggSumIf : ICustomAggregator
{
    double sum = 0;
  
	public void AddValue(SessionInfo sessionInfo, object value, params object[] args)
	{
        // Treat non-numbers as 0
        double input;
        if (!double.TryParse(value.ToString(), out input))
            return;
  
        bool isTrue;
        double number;
        // true, "true", and non-zero numbers are valid truthy values
        if ((bool.TryParse(args[0].ToString(), out isTrue) && isTrue) ||
            (double.TryParse(args[0].ToString(), out number) && number != 0))
            this.sum += input;
	}
  
	public object Result(SessionInfo sessionInfo)
	{
		return this.sum;
	}
}