How should I pass multiple parameters to an ASP.Net Web API GET?

I think the easiest way is to simply use AttributeRouting.

It's obvious within your controller, why would you want this in your Global WebApiConfig file?

Example:

    [Route("api/YOURCONTROLLER/{paramOne}/{paramTwo}")]    public string Get(int paramOne, int paramTwo)    {        return "The [Route] with multiple params worked";    }

The {} names need to match your parameters.

Simple as that, now you have a separate GET that handles multiple params in this instance.

Just add a new route to the WebApiConfig entries.

For instance, to call:

public IEnumerable<SampleObject> Get(int pageNumber, int pageSize) { ..

add:

config.Routes.MapHttpRoute(    name: "GetPagedData",    routeTemplate: "api/{controller}/{pageNumber}/{pageSize}");

Then add the parameters to the HTTP call:

GET //<service address>/Api/Data/2/10 

I just had to implement a RESTfull api where I need to pass parameters. I did this by passing the parameters in the query string in the same style as described by Mark's first example "api/controller?start=date1&end=date2"

In the controller I used a tip from URL split in C#?

// uri: /api/coursespublic IEnumerable<Course> Get(){    NameValueCollection nvc = HttpUtility.ParseQueryString(Request.RequestUri.Query);    var system = nvc["System"];    // BL comes here    return _courses;}

In my case I was calling the WebApi via Ajax looking like:

$.ajax({        url: '/api/DbMetaData',        type: 'GET',        data: { system : 'My System',                searchString: '123' },        dataType: 'json',        success: function (data) {                  $.each(data, function (index, v) {                  alert(index + ': ' + v.name);                  });         },         statusCode: {                  404: function () {                       alert('Failed');                       }        }   });

I hope this helps...