Dynamic Linq throws invalid cast exception

[Pete]

In my RadGridView I'm getting an invalid cast exception from CalculateAggregates when my aggregate function defined below is invoked:

var totalColumnAggregate = new AggregateFunction<DataRow, int?>
{
    AggregationExpression = target => target
        .AsQueryable()
        .Select("new(it[\"Foo\"] AS Foo)")
        .Cast<int?>()
        .Sum()
};

Any suggestions as to why?

Also, on another note, would the following be valid? (I'm trying to build this Select expression on the fly using Dynamic Linq Library)

.Select("new(it[\"Foo\"] AS Foo) + new(it[\"Bar\"] AS Bar) + new(it[\"FooBar\"] AS FooBar)")

[Rossen Hristov]

Hi Peter,

Could you please send us a small sample project demonstrating this behavior?

Thanks in advance.

Best wishes,
Ross
the Telerik team

[Pete]

Hi Ross;

This sample will demonstrate the behavior I'm seeing.

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Linq.Dynamic;

namespace DynamicLINQ
{
    class Program
    {
        static void Main(string[] args)
        {
            DataTable table = new DataTable();
            DataColumn a = new DataColumn();
            DataColumn b = new DataColumn();
            DataColumn c = new DataColumn();
            a.DataType = typeof(int);
            a.ColumnName = "A";
            b.DataType = typeof(int);
            b.ColumnName = "B";
            c.DataType = typeof(int);
            c.ColumnName = "C";

            table.Columns.Add(a);
            table.Columns.Add(b);
            table.Columns.Add(c);

            DataRow row = table.NewRow();
            row["A"] = 1;
            row["B"] = 2;
            row["C"] = 3;

            table.Rows.Add(row);

            var _source = row.Table.AsEnumerable().AsQueryable();


            //var results = _source.Select(i => i.Field<int>("A") + i.Field<int>("B") + i.Field<int>("C"))
            //    .Sum();


            // dynamic
            var _dynamicResults = _source.Select("new(it[\"A\"] AS A)").Cast<int>().Sum();

            Console.WriteLine(_dynamicResults.ToString());
            Console.ReadLine();

        }
    }
}

[Rossen Hristov]

Hello Peter,

Unfortunately, I can not see any Telerik controls involved in your sample code.

Does your code work with the standard toolkit DataGrid or with a standard ListBox?

In case you are having problems with RadGridView, could you please prepare a runnable sample project that demonstrates the exact problem you are having with RadGridView and then send it to me.

I will debug it to see what is going on.

Thanks in advance.

Greetings,
Ross
the Telerik team

[Pete]

Hello again Ross;

Thanks for the feedback. It looks like the issue is in the Dynamic Linq Library. When I have it sorted out I'll post the answer/solution for others who may have the same issue.

Thanks again for your timely replies.