linq orderby using property name string

Question

I have a list which I need to order eg.

var list = someelements;

I also have a parameter which says by which property and what direction I should order list data eg.

var sortby = "Name";
var sortdirection = "desc";

I was wondering if I can match string property name with the right property so I get:

var list = someelements.OrderBy(x => x.Name).ToList();

when sortby == "Name" without the need of using switch loop to check property name and assign a correct property to OrderBy.

Same I would like to achieve with select either OrderBy or OrderByDescending depending whether I get sortdirection = "asc" or sortdirection = "desc"

Is it possible and if yes, how?

Relying on `OrderBy` or on `OrderByDescending` on acount of the `sortDirection` values is quite straightforward: use a condition (even a ternary operator would do the job in this situation). — varocarbas, Nov 30 '15 at 16:16
Possible duplicate of [How can I do an OrderBy with a dynamic string parameter?](https://stackoverflow.com/questions/2728340/how-can-i-do-an-orderby-with-a-dynamic-string-parameter) — mkimmet, Sep 07 '17 at 20:20

score 6 · Accepted Answer · answered Nov 30 '15 at 16:13

6

You can get Dynamic Linq through Nuget. Then you can use .OrderBy(sortby + " " + sortdirection). Here is the link: Dynamic Linq.

answered Nov 30 '15 at 16:13

Aleksa

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Thanks for the answer, I used the port of this library for .net core: https://www.nuget.org/packages/System.Linq.Dynamic.Core – MIP1983 Oct 11 '17 at 13:54

score 4 · Answer 2 · answered Nov 30 '15 at 16:27

Here is one solution that does not use Dynamic Linq:

public class Helper
{
    public static IEnumerable<T> OrderByDynamic<T>(IEnumerable<T> items, string sortby, string sort_direction)
    {
        var property = typeof (T).GetProperty(sortby);

        var result = typeof(Helper)
            .GetMethod("OrderByDynamic_Private", BindingFlags.NonPublic | BindingFlags.Static)
            .MakeGenericMethod(typeof (T), property.PropertyType)
            .Invoke(null, new object[]{ items, sortby, sort_direction});

        return (IEnumerable<T>)result;
    }

    private static IEnumerable<T> OrderByDynamic_Private<T,TKey>(IEnumerable<T> items, string sortby, string sort_direction)
    {
        var parameter = Expression.Parameter(typeof (T), "x");

        Expression<Func<T, TKey>> property_access_expression =
            Expression.Lambda<Func<T, TKey>>(
                Expression.Property(parameter, sortby),
                parameter);

        if (sort_direction == "asc")
        {
            return items.OrderBy(property_access_expression.Compile());
        }

        if (sort_direction == "desc")
        {
            return items.OrderByDescending(property_access_expression.Compile());
        }

        throw new Exception("Invalid Sort Direction");
    }
}

You can use it like this:

var result = Helper.OrderByDynamic(list, "Name", "desc").ToList();

linq orderby using property name string

2 Answers2

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