ASP.NET Web API GET Method: Passing multiple values for single parameter

Question

I am fairly new to ASP.NET Web API.

I am trying to build an API method that can handle multiple values for a single parameter from a search client.

The criteria needs to be a OR search for eg. A color search for Red OR Blue OR Green.

I pass the colors as integer to my method. Please find my controller method below which fails to compile with the following error

Errors:

Error 1 'int' does not contain a definition for 'Contains' and the best extension method overload 'System.Linq.ParallelEnumerable.Contains(System.Linq.ParallelQuery, TSource)' has some invalid arguments

Error 2 Instance argument: cannot convert from 'int' to 'System.Linq.ParallelQuery'

Code:

public IQueryable<Items> GetItemByColour(string Colour)
{
    int[] intArr = Array.ConvertAll(Colour.Split(','), s => int.Parse(s));

    var query = from a in db.Items
                where a.ItemsColour.Contains(intArr)
                select a;

    return query;
}

Answer 1

You seem to have two different issues there. The first one is that you don't need to send the Colors list as a string and convert it to an integer array manually, you can do it like this instead:

public IQueryable<Items> GetItemByColour([FromUri] int[] Colour)

And you're getting an error in your LINQ query because a.ItemColour is an integer, not an integer list, therefore you can't use the Contains extension method on it. You have to do it like this (assuming Colour is now an integer array):

var query = from a in db.Items
            where Colour.Contains(a.ItemsColour)
            select a;

return query;