想要将对象从MVC控制器传递到Web API控制器

Question

This is my MVC Controllers code.

[HttpPost]
public async Task<IActionResult> InsertNewStudentAsync(ViewModel.StudentPersonalDetailsViewModel ob)
{
    StudentModel obj = ViewModel.StudentPersonalDetailsViewModel.Translate(ob);
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri("http://localhost:52494/");
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        var bodyData = ViewModel.StudentPersonalDetailsViewModel.Translate(ob);

        //HttpContent ob = new HttpContent();
        var response = await client.PostAsync("api/Student/InsertStudent",obj);
    }
    return View();
}

In the line var response = await client.PostAsync("api/Student/InsertStudent",obj);

It is showing me an error on obj showing that

Error CS1503 Argument 2: cannot convert from 'SMS.Domain.Models.StudentModel' to 'System.Net.Http.HttpContent'

How do I pass that object to my API's controller.

Answer 1

That is because it is expecting a HttpContent derived class.

Either use the PostAsJsonAsync extension method

var response = await client.PostAsJsonAsync("api/Student/InsertStudent",obj);

or convert it yourself

var json = JsonConvert.SerializeObject(obj); 
var content = new StringContent(json, Encoding.UTF8, "application/json");
var response = await client.PostAsync("api/Student/InsertStudent", content);

Which is basically what the extension method is doing under the hood.

Here is an example of rolling your own extension method if you do not want to add additional dependencies.

public static Task<HttpResponseMessage> PostAsJsonAsync<T>(this HttpClient client, string requestUri, T obj) {
    var json = JsonConvert.SerializeObject(obj); 
    var content = new StringContent(json, Encoding.UTF8, "application/json");
    return client.PostAsync(requestUri, content);    
}