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

Program Code

public class AggJoin : ICustomAggregator
{
    System.Text.StringBuilder stringBuilder = new System.Text.StringBuilder();
    string delimiter = ", ";
    
	public void AddValue(SessionInfo sessionInfo, object value, params object[] args)
	{
        // Skip blank values
	 if (value == null || value.ToString() == string.Empty)
            return;
        
        if (args.Length != 0)
        	this.delimiter = args[0].ToString();
        
        this.stringBuilder.Append(value);
        this.stringBuilder.Append(this.delimiter);
	}

	public object Result(SessionInfo sessionInfo)
	{
        string retVal = this.stringBuilder.ToString();
        
        // Remove the trailing delimiter
        if (this.delimiter.Length > 0 && retVal.Length > 0)
            retVal = retVal.Remove(retVal.Length - this.delimiter.Length);
        
        return retVal;
	}
}