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;
}

Meryovi · Accepted Answer · 2013-07-28 15:23:23Z

4

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;

answered Jul 28, 2013 at 15:23

Meryovi

6,2215 gold badges44 silver badges67 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Ayman H Over a year ago

Thanks for the quick response, its definitely the correct way. The only problem is I am using WP8 app to consume the Web API and use a Web Client. Not sure how you would pass an array using a Web Client

Meryovi Over a year ago

It's fairly easy, you do it like this: example-url.com/?Colour=1&Colorur=2&Colour=3. In this example, every instance of the Colour query-string variable will be an item in the Colour array. This way your service is also more interoperable. Regarding your question, I did also point out the other issue you had and how to solve it. :)

Erik Philips Over a year ago

This is by far the best way to go. By passing a string, it requires you to do type checking to prevent any int.Parse FormatExceptions.

Ayman H Over a year ago

that's perfect! Wasn't aware of that. Wasted 3 hours of my life trying to get it work earlier!

Lajos Arpad · Accepted Answer · 2013-07-28 15:33:15Z

0

I suppose this will be the solution to your issue:

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

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

    return query;
}

The problem was that you were looking for the presence of an array in an int. You need to look for the presence of an int in the array

answered Jul 28, 2013 at 15:33

Lajos Arpad

80.4k42 gold badges122 silver badges234 bronze badges

Collectives™ on Stack Overflow

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

2 Answers 2

4 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related