I'm trying to use a WebApi to get a list of Employees from my data base, using this code: This is the code of my client MVC Application:
string u = "http://localhost:1411/api/EmployeeAPI";
Uri uri = new Uri(u);
HttpClient httpClient = new HttpClient();
Task<HttpResponseMessage> response = httpClient.GetAsync(uri);
Task.WaitAll(response);
HttpResponseMessage resposta = response.Result;
var msg = resposta.Content.ReadAsStringAsync().Result;
Employee[] employees = JsonConvert.DeserializeObject<Employee[]>(msg);
return View(employees);
And this is the code of my WebAPI:
public IEnumerable<Employee> GetEmployees()
{
return db.Employees.AsEnumerable();
}
But this error keeps popping up and I can't understand why:
Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'DataAccess.Employee[]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly. To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object. Path 'Message', line 1, position 11.
My Employee Class:
namespace DataAccess
{
using System;
using System.Collections.Generic;
public partial class Employee
{
public Employee()
{
this.Products = new HashSet<Product>();
}
public int EmployeeId { get; set; }
public string Title { get; set; }
public string FirstName { get; set; }
public string MiddleName { get; set; }
public string LastName { get; set; }
public byte[] rowguid { get; set; }
public System.DateTimeOffset ModifiedDate { get; set; }
public virtual ICollection<Product> Products { get; set; }
}
}
The Json output I'm not really sure how to get it
The msg variable content:
My msg variable returns
"{\"Message\":\"An error has occurred.\",\"ExceptionMessage\":\"The 'ObjectContent`1' type failed to serialize the response body for content type 'application/json; charset=utf-8'.\",\"ExceptionType\":\"System.InvalidOperationException\",\"StackTrace\":null,\"InnerException\":{\"Message\":\"An error has occurred.\",\"ExceptionMessage\":\"Self referencing loop detected with type 'System.Data.Entity.DynamicProxies.ProductSubCategory_9EC9A3706390DE6A3B51F713F0DDAC2162AFB5B3FAB8F8587C9A865333A7729A'. Path '[0].Products[0].ProductSubCategory.ProductCategory.ProductSubCategories'.\",\"ExceptionType\":\"Newtonsoft.Json.JsonSerializationException\",\"StackTrace\":\" at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.CheckForCircularReference(JsonWriter writer, Object value, JsonProperty property, JsonContract contract, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeList(JsonWriter writer, IWrappedCollection values, JsonArrayContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeList(JsonWriter writer, IWrappedCollection values, JsonArrayContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeList(JsonWriter writer, IWrappedCollection values, JsonArrayContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value)\r\n at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value)\r\n at System.Net.Http.Formatting.JsonMediaTypeFormatter.<>c__DisplayClassd.b__c()\r\n at System.Threading.Tasks.TaskHelpers.RunSynchronously(Action action, CancellationToken token)\"}}"
Employee
class – Yuval Itzchakov