Learning and implement LINQ concepts with .NET 2.0

In sql, we familiar to use key like "select", "where", "order by", and more.

Now, i'am try to implement that into .NET 2.0

Example:

col1	col2
Ronald	True
Eriawan	True
Nicko	False

How to get col1 members where col2 value is True ?

SQL-Query

SELECT [col1] FROM [tbl] WHERE [col2] = 'True' ;

.NET 2.0

//Give condition

IEnumerable<DataRow> iEnumDataRow= csQuery.Where<DataRow>(Datarow [], delegate(DataRow row) { return Convert.ToBoolean(row[col2]) ; }) ;

//Get Data

IEnumerable<string> iEnumString = csQuery.Select<DataRow, string>(iEnumDataRow, delegate(DataRow row) { return row[col1].ToString(); });

//View Data

List<string> listString = new List<string>(iEnumString);

How it running successfull?

Lets make the simple class, for example csQuery.

public delegate TResult Func<TSource, TResult>(TSource arg);

public static class csQuery

{

    public static IEnumerable<TSource> Where<TSource>(IEnumerable<TSource> source, Func<TSource, bool> predicate)

    {

        if (source == null)

            throw new ArgumentNullException(source.GetType().ToString()); 

        if (predicate == null)

            throw new ArgumentNullException(predicate.GetType().ToString()); 

        return WhereIterator<TSource>(source, predicate);

    }

    private static IEnumerable<TSource> WhereIterator<TSource>(IEnumerable<TSource> source, Func<TSource, bool> predicate)

    {

        foreach (TSource var in source)

        {

            if (predicate(var))

                yield return var;

        }

    }

    public static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector)

    {

        if (source == null)

            throw new ArgumentNullException(source.GetType().ToString()); 

        if (selector == null)

            throw new ArgumentNullException(selector.GetType().ToString()); 

        return SelectIterator<TSource, TResult>(source, selector);

    } 

    private static IEnumerable<TResult> SelectIterator<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector)

    {

        foreach (TSource var in source)

        {

            yield return selector(var);

        }

    }

}