no SourceField for EnumerableAggregateFunction

[Brian Graves]

I have written my own custom aggregate function to count distinct column values (since the CountFunction class doesn't offer this currently).  Unfortunately, there's is no SourceField property to set and I end up having to write a new count function for every single column in my grid.  How can I pass the column name (or SourceField) to my counting method?  Here's my code:

    public class CountDistinct : EnumerableAggregateFunction
    {
        private string _columnName;
        public CountDistinct(string columnName)
        {
            _columnName = columnName;
            //SourceField = columnName; DOESN'T EXIST
        }

        protected override string AggregateMethodName
        {
            get
            {
                return "CountDistinct";
            }
        }

        protected override Type ExtensionMethodsType
        {
            get
            {
                return typeof(CountAggregates);
            }
        }
    }

    public class CountAggregates
    {
        public static int CountDistinct<TSource>(IEnumerable<TSource> source)
        {
            Dictionary<string, string> dUniqueValues = new Dictionary<string, string>();

            foreach (TSource item in source)
            {
                PropertyInfo colNameProp = item.GetType().GetProperty(SourceField);
                string value = colNameProp.GetValue(item, null).ToString().ToLower();
                if (!dUniqueValues.ContainsKey(value))
                    dUniqueValues.Add(value, "whatever");
            }

            return dUniqueValues.Keys.Count;
        }
    }

[Brian Graves]

I ended up using the EnumerableSelectorAggregateFunction class to do this.  See link:
http://www.telerik.com/community/forums/silverlight/gridview/footer-sum-of-one-or-more-fields.aspx

[Milan]

Hello Brian Graves,

Thank you for sharing your findings with the community.

I have updated your Telerik points.

All the best,
Milan
the Telerik team

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