How I can read parameter value from controller constructor in asp.net web API 2 ??
public class DataController : ApiController
{
private APIMgr apiMgr ; // APIMgr custome class
public DataController()
{
// var id = Request.GetRouteData(); = 5 // this parameter must send with alla request "http://localhost/TAPI/api/data/5"
apiMgr= new apiMgr(id);
}
The HttpContext is not set when the controller class is constructed , but it set ("injected") later by the ControllerBuilder class .
According to this I can to access the HttpContext by override "Initialize" method .
This page explains ASP.NET MVC request flow
protected override void Initialize(HttpControllerContext controllerContext)
{
base.Initialize(controllerContext);
}
You cannot read route parameters from within a constructor...only from an action method. You'll need to define an appropriate route with expected templates. Take a look at the default controller in your route config in WebApiConfig.cs
Also HttpContext is not accessible from within a controller constructor.
You can't. To read parameter values in action methods there are a few ways. Let us assume a model that represents a person.
public class Person
{
public Guid Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
Now let us assume that we with to have an API method that enables us to send a representation of a person to the server that will then save it to some data store. For this purpose we implement a POST method that accepts parameters to build our person object. There are a few ways we could do this.
Method 1: Bind parameters from the request body
public IHttpActionResult Post([FromBody]Person person)
{
// validate your parameter in some way
if (person.Equals(default(Person))) return BadRequest("person must not be null");
// go off and save the person
var createdPerson = myPersonRepository.Save(person);
if (createdPerson == default(Person)) return InternalServerError();
return CreatedAtRoute("DefaultApi", new { id = createdPerson.Id }, createPerson);
}
This requires you to pass a JSON representation of your person in the request body. Something like the following should do it.
{
"firstname": "Luke",
"lastname": "Skywalker"
}
Method 2: Bind parameters from the request URL query string
public IHttpActionResult Post([FromUri]Person person)
{
// validate your parameter in some way
if (person.Equals(default(Person))) return BadRequest("person must not be null");
// go off and save the person
var createdPerson = myPersonRepository.Save(person);
if (createdPerson == default(Person)) return InternalServerError();
return CreatedAtRoute("DefaultApi", new { id = createdPerson.Id }, createPerson);
}
This requires you to pass the parameter values in the query string, for example:
http://mywhizzyapi/api/people?firstname=luke&lastname=skywalker
Method 3: Explicitly pass parameters and create the object yourself
public IHttpActionResult Post(string firstname, string lastname)
{
// validate your parameter in some way
if (id.Equals(Guid.Empty)) return BadRequest("id must not be null or an empty GUID");
if (string.IsNullOrEmpty(firstname)) return BadRequest("firstname must not be null or empty");
if (string.IsNullOrEmpty(lastname)) return BadRequest("lastname must not be null or empty");
// create your person object
var person = New Person {
id = id,
firstName = firstname,
lastname = lastname,
};
// go off and save the person
var createdPerson = myPersonRepository.Save(person);
if (createdPerson == default(Person)) return InternalServerError();
return CreatedAtRoute("DefaultApi", new { id = createdPerson.Id }, createPerson);
}
This method also requires you to pass the parameter values in the query string, for example:
http://mywhizzyapi/api/people?firstname=luke&lastname=skywalker
But in the last case as mentioned you have to bind the parameters explicitly to your model.
