如何在asp.net WEB API中传递多个querystring参数

Question

I want to know how can I pass multiple querystring values to my web api project. I made one by referring tutorial in which I can pass the ID.

// GET: api/Product
        public IQueryable<product> Getproducts()
        {
            return db.products;
        }

        // GET: api/Product/5
        [ResponseType(typeof(product))]
        public IHttpActionResult Getproduct(int id)
        {
            product product = db.products.Find(id);
            if (product == null)
            {
                return NotFound();
            }

            return Ok(product);
        }

Please help me to understand what if I have multiple parameters to pass & how can I do it with querystring

UPDATE

public class ProductController : ApiController
    {
        public IEnumerable<product> Get()
        {
            using(foxbop7g_foxbox_mainEntities entities = new foxbop7g_foxbox_mainEntities())
            {
                return entities.products.ToList();
            }
        }

        public product Get(string status)
        {
            using (foxbop7g_foxbox_mainEntities entities = new foxbop7g_foxbox_mainEntities())
            {
                return entities.products.FirstOrDefault(e => e.status == status);
            }
        }
    }

Answer 1

Please help me to understand what if I have multiple parameters to pass & how can I do it with querystring

You could just add them as parameters to your method. For instance if there was a meaning to get a product by specifying product id and category you could define this:

[ResponseType(typeof(product))]
public IHttpActionResult Getproduct(int id, string category)

This is the common solution if you have to do this for a GET request. (GET request has not a body as POST or PUT etc. requests). If you have a POST, PUT, ...request, you could match your values by defining a model (a class with the properties you want to receive from the POST,PUT...), then define this as the only parameter of the method and prefix it with [FromBody] attribute.

Eg

[HttpPut]
public IHttpActionResult Customer([FromBody] CustomerModel)

and

public class CustomerModel
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int Age { get; set; }
}

Answer 2

If you search for specific record use Single or SingleOrDefault method with lambda expression (p => p.id). By SingleorDefault you execute query. Find is possible onnly when lazy loading is enabled. If you search for many use Where(also with lambda expression) and don't forget to add .ToList(); in the end as you want to iterate them to display for example. If there are foreign keys use .Include for eager loading.

Answer 3

You can accomplish that in one of the following ways:

1. Uri binding (Using [FromUri]) : You can pass the parameters in the url and then decorate the action parameter with [FromUri] attribute. for example: your method could be something like public HttpResponseMessage Get([FromUri]String someInput1, [FromUri]String someInput2) {} And you request uri can be like ...?someInput1=param1&someInput2=param2

2. from Request.GetQueryNameValuePairs(): this will get you all the query parameter as an eumerable key-value pair. Then you can do something like:

 var queryStrings = Request.GetQueryNameValuePairs(); var key = "queryKey";//forexample:"someInput1" in the above url var match = queryStrings.FirstOrDefault(keyValue =>String.Compare(keyValue.Key,key,StringComparison.OrdinalIgnoreCase)==0); var value = match.Value; 

---

Check these links for further understanding:

1. https://www.strathweb.com/2013/04/asp-net-web-api-parameter-binding-part-1-understanding-binding-from-uri/

2. https://docs.microsoft.com/en-us/aspnet/web-api/overview/formats-and-model-binding/parameter-binding-in-aspnet-web-api