Xamarin.Form HttpClient for WebAPI failed in iOS - asp.net-web-api

Question

I'm creating Xamarin.Forms for Android and iOS using WebAPI as the web service. The whole thing went well in Android but I hit error in iOS, particularly when doing "JsonConvert.DeserializeObject". Below is the sample code
Model
public class WsObjTest
{
public string name { get; set; }
public string code { get; set; }
public string age { get; set; }
}
WebAPI
[HttpGet]
public WsObjTest HelloWorld()
{
WsObjTest wsObjTtest = new WsObjTest();
wsObjTtest.name = "John Doe";
wsObjTtest.code = "ABC123";
wsObjTtest.age = "18";
return wsObjTtest ;
}
In my Xamarin.Forms, this is how I call and deserialize the response
HttpClient client = new HttpClient();
var response = await client.GetStringAsync(apiURL.Replace("##action##", "HelloWorld"));
return JsonConvert.DeserializeObject<WsObjTest>(response); //ERROR HERE
I got the response as below, but error thrown at the return statement.
"{\"code\":\"ABC123\",\"name\":\"John Doe\",\"age\":\"18\"}"
The error message is below
Unhandled Exception:
System.MemberAccessException: Cannot create an abstract class:
System.Reflection.Emit.DynamicMethod occurred
I think it's because iOS doesn't support JIT compilation or dynamic methods of some sort? May I know if there is anyway to overcome this error? Thanks.

Answer 1

Based on https://learn.microsoft.com/en-us/xamarin/ios/internals/limitations, it is not possible to use any facilities that require code generation at runtime in Xamarin.iOS because code on the iPhone is statically compiled ahead of time instead of being compiled on demand by a JIT compiler.
What I have to do now is read and create the object manually as below. Should anybody got better solution please share with me.
HttpClient client = new HttpClient();
var response = await client.GetStringAsync(apiURL.Replace("##action##", "HelloWorld"));
JObject jObject = (JObject) JsonConvert.DeserializeObject(response);
WsObjTest wsObjTest = new WsObjTest();
wsObjParent.name = jObject["name"].ToString();
wsObjParent.code = jObject["code"].ToString();
wsObjParent.age = jObject["age"].ToString();
return wsObjTest;
Extracted from the link
Since the iOS kernel prevents an
application from generating code dynamically, Xamarin.iOS does not
support any form of dynamic code generation. These include:
The System.Reflection.Emit is not available.
No support for
System.Runtime.Remoting.
No support for creating types dynamically (no
Type.GetType ("MyType`1")), although looking up existing types
(Type.GetType ("System.String") for example, works just fine).
Reverse
callbacks must be registered with the runtime at compile time.
So the System.Reflection.Emit thus the error that I received.