OrderBy Column Name as String using Linq C# .Net Dynamic Sorting of Anonymous Types

If you’re familiar with Linq, you have undoubtedly used the popular “OrderBy” extension method. Unfortunately, this method does not accept a string value with the column name.

var data = from i in db.tablename
select i;

repeatername.datasource = data.OrderBy(i=>i.columnname); //this works

repeatername.datasource = data.OrderBy("columnname"); //this does not

To resolve, you can add the following small class or just the method to a generic DLL you use in your web application projects or create a new class or project for your extension methods.

Kudos to R. Prestol for help researching this one.

using System.Linq;
using System.Linq.Expressions;
using System;

namespace YourAppName.Web
{
    public static class extensionmethods
    {
        public static IQueryable<T> OrderByField<T>(this IQueryable<T> q, string SortField, bool Ascending)
        {
            var param = Expression.Parameter(typeof(T), "p");
            var prop = Expression.Property(param, SortField);
            var exp = Expression.Lambda(prop, param);
            string method = Ascending ? "OrderBy" : "OrderByDescending";
            Type[] types = new Type[] { q.ElementType, exp.Body.Type };
            var mce = Expression.Call(typeof(Queryable), method, types, q.Expression, exp);
            return q.Provider.CreateQuery<T>(mce);
        }
    }
}

Returning to our first code snippet, you can now do:

repeater.datasource = data.OrderByField("columnname");

Since this is an extension method, and exists in a class within the same namespace as your project or other referenced assembly, you can call the method directly from the IQueryable Linq data object without requiring any other inherits; this works similar to override functionality.

Read up about extension methods on MSDN or Google for other cool tricks you can do. Enjoy. Image may be NSFW.
Clik here to view.

References
Extension Methods (MSDN), http://msdn.microsoft.com/en-us/library/bb383977.aspx

Image may be NSFW.
Clik here to view.

Image may be NSFW.
Clik here to view.