StormPooper StormPooper -4 years ago 69
C# Question

Passing a list of int to a HttpGet request

I have a function similar in structure to this:

[HttpGet]
public HttpResponseMessage GetValuesForList(List<int> listOfIds)
{
/* create model */

foreach(var id in listOfIds)
model.Add(GetValueForId(id)

/* create response for model */
return response;
}


However, when I do a Get request for the method:

{{domain}}/Controller/GetValuesForList?listOfIds=1&listOfIds=2


I get an error when debugging stating that
listOfIds
is null. In our controller we have a number of public HttpGet methods that work fine, and when changing the parameter to a single int it works. I've tried changing the parameter type to
int[]
and
IEnumerable<int>
too, but no change.

However, when changing the call to a HttpPost and passing the list as an x-www-form-urlencoded value, the method works.

Is it possible to pass a list to a Get method, or will I have to use Post? Since it's not actually a post method (as it returns a JSON model of values and nothing is saved to the server).

Answer Source

If you are using MVC WebAPI, then you can declare your method like this:

[HttpGet]
public int GetTotalItemsInArray([FromUri]int[] listOfIds)
{
       return listOfIds.Length;
}

and then you query like this: blabla.com/GetTotalItemsInArray?listOfIds=1&listOfIds=2&listOfIds=3

this will match array [1, 2, 3] into listOfIds param (and return 3 as expected)

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