Question

I am creating a C# 2010 application using .NET Framework 3.5.

I have a datagridview that contains a few columns and rows [obviously]. I save this datagridview’s rows in a structure of the form List<string[]>. I also have a List<double> which contains coefficients. I want to sort the structure by the coefficients using the System.LINQ library. I have attempted the following:

var linq_Query_rowrates =
    from rw in rows
    orderby matchrate descending
    select rw;

This underlines the rows in the query and shows the following error:

Error 1 Could not find an implementation of the query pattern for source type ‘System.Collections.Generic.List<string[]>‘. ‘OrderByDescending‘ not found. Are you missing a reference to ‘System.Core.dll‘ or a using directive for ‘System.Linq‘?

Is it possible to sort this kind of structure using the LINQ library and if yes, how?

Note: I am aware of a lot of other methods to accomplish this, I am just interested in doing it using the LINQ library.

Note: matchrate is not a member of rows but using a member of rows does not work either.

LATER EDIT: Maybe it should be something like this?

        var linq_Query_rowrates =
            from rw in rows
            join rate in matchrate
            on matchrate equals rows
            orderby matchrate descending
            select rw;

Answer 1

It’s ugly, but it’s Linq:

            List<string[]> rows = null;
            List<double> coefficients = null;

            rows
                .Select((row, index) => new { Row = row, Index = index })
                .Join(coefficients
                            .Select(
                                (coefficient, index) => new { Coefficient = coefficient, Index = index }), 
                                x => x.Index, 
                                x => x.Index, 
                                (rowIndex, coefIndex) => new { Row = rowIndex.Row, Coefficient = coefIndex.Coefficient })
                .OrderBy(x => x.Coefficient)
                .Select(x => x.Row);

I haven’t tested it though. It should be possible to transform it to query form.