json - 如何在 Controller 中调用 web api 并返回 View MVC4

Question

我有一个使用MVC4的项目，我想问一下如何从webapi获取数据并返回到 View 中。

型号

public class Name
{
    public Int32 NameId { get; set; }
    public String FirstName{ get; set; }
    public String LastName{ get; set; }
    public String CreatedBy { get; set; }
}

public class IListMyProject
{
    public List<Name> Names { get; set; }
}

我可以在我的 Index.cshtml 中列出所有内容使用此代码

public ActionResult Index()
    {
        string securityToken = repo.GetTokens();
        if (securityToken != null)
        {
            HttpClient client = new HttpClient();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            HttpRequestMessage httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "webapiurl/api/Name/Get?$orderby=LastName&$top=10");
            string authHeader = System.Net.HttpRequestHeader.Authorization.ToString();
            httpRequestMessage.Headers.Add(authHeader, string.Format("JWT {0}", securityToken));
            var response = client.SendAsync(httpRequestMessage)
                .ContinueWith((postTask) => postTask.Result.EnsureSuccessStatusCode())
                .Result;
            if (response.IsSuccessStatusCode)
            {
                model.Names = response.Content.ReadAsAsync<IList<Name>>().Result.ToList();

            }
        }
        return View("Index", model);
    }

我可以回复我的观点。现在我有另一个名为 Details.cshtml 的 View ，其中包含以下代码:

 public ActionResult Details(string id)
    {
        string securityToken = repo.GetTokens();
        if (securityToken != null)
        {
            HttpClient client = new HttpClient();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            HttpRequestMessage httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "webapiurl/api/Name/GetById/"+id+"");
            string authHeader = System.Net.HttpRequestHeader.Authorization.ToString();
            httpRequestMessage.Headers.Add(authHeader, string.Format("JWT {0}", securityToken));

            var response = client.SendAsync(httpRequestMessage)
                .ContinueWith((postTask) => postTask.Result.EnsureSuccessStatusCode())
                .Result;
            if (response.IsSuccessStatusCode)
            {

                model.Names = response.Content.ReadAsAsync<IList<Name>>().Result.ToList();

            }
        }
        return View(model);
    }

对于此 Detail，我的 Json 如下所示:

 application/json, text/json
 {
  "NameId": 1,
  "FirstName": "This is First Name",
  "LastName": "This is Last Name",
  "CreatedBy": "This is Created By"
 }

当我运行它时，我收到此错误:

 Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.IList`1[Models.Name]' 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<T>) 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 'NameId', line 1, position 10.

我该如何解决这个问题，我是 webapi 的新手。我想知道为什么如果我列出所有(对于索引，我使用 api/get)它可以工作，但是当我想详细显示它时，它不起作用。

感谢帮助

问候

编辑

当我调试

 model.Names = response.Content.ReadAsAsync<IList<Name>>().Result.ToList();

它说 Null，当我尝试获得响应时有什么问题吗？

Answer 1

问题是:

{
  "NameId": 1,
  "FirstName": "This is First Name",
  "LastName": "This is Last Name",
  "CreatedBy": "This is Created By"
}

不能反序列化为 IList。您上面的 JSON 只是一个名称，而不是名称的集合。所以 Json.NET 反序列化会失败。

确保您的 Web API Controller 返回一个 IList，或者更改您的 MVC 代码以将内容作为单个名称读取。 JSON 中的名称集合看起来像这样:

[{
  "NameId": 1,
  "FirstName": "This is First Name",
  "LastName": "This is Last Name",
  "CreatedBy": "This is Created By"
},
{
  "NameId": 2,
  "FirstName": "This is First Name",
  "LastName": "This is Last Name",
  "CreatedBy": "This is Created By"
}]