System.Linq.Dynamic does not support OrderByDescending("someColumn")?

Question

Ok so in our project I'm using System.Linq.Dynamic library but I just noticed that I cannot do the following:

myDataSource.OrderByDescending("someColumnName")

Because I get the following error:

Overload resolution failed because no accessible OrderByDescending can be called with these arguments...

It seems that the Library only support OrderBy("someColumnName"). Is there a reason for this and how would I bypass this issue if I want to reorder the records in descending order? Do I have to user Reverse() for example OrderBy("someColumnName").Reverse()? Seems like a hack...

Any advice would be greatly appreciated...

Solution 1

Assuming that you are using the DynamicQuery Helper files from the Microsoft sample library (Which are in the namespace System.Linq.Dynamic) then after reading the source code it looks like you need to specify the ordering you want as follows:

myDataSource.OrderBy("someColumnName descending")

Solution 2

If you're using string values (like me) you'll have to concatenate it to the string like this:

myDataSource.OrderBy(columnName + " descending");

Don't forget to add a space before 'descending' otherwise you'll get an error.

Comments

[Sebastian Siek]

I thought that OrderByDescending method does not accept only 1 string parameter ?!

[Leom Burke]

Sorry - I mistyped the answer. The OrderBy method in the DynamicQuery helper from Microsoft allows you to specify comma-separated string orderings such as this.

[Marko]

Yes this was the answer I was looking for. If I might add you can actually just say myDataSource.OrderBy("someColumnName DESC") in other words you don't have to type the entire descending word.

[Pinte Dani]

Works, although not intuitive at all from the Framework design. It would have been more clear if System.Linq.Dynamic would contain also a method for OrderByDescending which accepts only a string parameter, like OrderBy