6

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

模型

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Index.cshtml使用此代码列出所有内容

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);
    }

我可以返回我的观点。现在我有另一个名为 Details.cshtml 的视图，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);
    }

对于这个细节，我的 Json 看起来像这样：

 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，我得到这个错误：

 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

当我调试时

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

它说空，当我尝试得到响应时有什么问题吗？

4

3 回答 3

3

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 控制器返回一个 IList，或更改您的 MVC 代码以将内容作为单个名称读取。JSON 中的名称集合将如下所示：

[{
  "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"
}]
于 2013-02-09T04:32:31.047 回答
1

问题似乎是当您将结果读取为 .json 时，您的 JSON 仅返回 1 条记录IList<Name>。将其更改为简单Name应该可以解决问题。

但是您的问题是：“如何在控制器中调用 web api 并返回视图 MVC4 ”

我建议您查看http://restsharp.org/您可以将代码简化为：

public ActionResult Details(string id)
{
    string securityToken = repo.GetTokens();
    Name model;
    if (securityToken != null)
    {
        var client = new RestClient("");

        var request = new RestRequest("webapiurl/api/Name/GetById/"+id, HttpMethod.Get);
        string authHeader = System.Net.HttpRequestHeader.Authorization.ToString();
        request.AddHeader(authHeader, string.Format("JWT {0}", securityToken));

        var model = client.Execute<Name>(request);
    }
    return  View(model);
}
于 2013-02-18T16:25:33.803 回答
1

Web API 返回一个Name类型的对象，而不是 Name 的集合。我看不到您在哪里定义model。我添加了Name类型的定义。尝试这个。

public ActionResult Details(string id)
{
    string securityToken = repo.GetTokens();
    Name model;
    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 = response.Content.ReadAsAsync<Name>();

        }
    }
    return  View(model);
}
于 2013-02-12T13:53:38.970 回答