Question

我正在使用SP 2013编写Provider Hosted APP，我有一个数据层，它在共享点列表上使用REST到CRUD。现在我得到了JSON格式的List项目但是我无法遍历列表数据你可以帮忙做到这一点吗？（是否有任何可以反序列化的列表项类？）

这是代码

public JToken GetListData(string webUrl, string userName, SecureString password, string listTitle)
        {
            using (var client = new WebClient())
            {
                client.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f");
                client.Credentials = new SharePointOnlineCredentials(userName, password);
                client.Headers.Add(HttpRequestHeader.ContentType, "application/json;odata=verbose");
                client.Headers.Add(HttpRequestHeader.Accept, "application/json;odata=verbose");
                var endpointUri = new Uri(new Uri(webUrl), string.Format("/sites/DTF/_api/web/lists/getbytitle('{0}')/Items", listTitle));
                var result = client.DownloadString(endpointUri);
                var t = JToken.Parse(result);
                return t["d"];
            }
        }

Answer 1

您需要使用DataContractJsonSerializer类来反序列化数据，如下所示：

http://www.codeproject.com/Articles/272335/JSON-Serialization-and-Deserialization-in-ASP-NET

要完成这项工作，你必须创建与Json结构相匹配的类。最简单的方法是将原始Json响应复制到一个工具中，该工具将生成类似这样的类：

http://json2csharp.com/

您需要生成的实际类会根据您在REST响应中获得的数据结构而有所不同。这是我创建的一个示例，它演示了发出请求，解析Json Response并根据结果下载文件：

public class JsonHelper
{
    /// JSON Serialization
    public static string JsonSerializer<T>(T t)
    {
        DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
        MemoryStream ms = new MemoryStream();
        ser.WriteObject(ms, t);
        string jsonString = Encoding.UTF8.GetString(ms.ToArray());
        ms.Close();
        return jsonString;
    }
    /// JSON Deserialization
    public static T JsonDeserialize<T>(string jsonString)
    {
        DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
        MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));
        T obj = (T)ser.ReadObject(ms);
        return obj;
    }
}

//Custom Json Classes
public class RootObject
{
    public D d { get; set; }
}
public class D
{
    public GetContextWebInformation GetContextWebInformation { get; set; }
    public List<Result> results { get; set; }
}
public class GetContextWebInformation
{
    public int FormDigestTimeoutSeconds { get; set; }
    public string FormDigestValue { get; set; }
    public string LibraryVersion { get; set; }
    public string SiteFullUrl { get; set; }
    public string WebFullUrl { get; set; }
}
public class Result
{
    public ContentType ContentType { get; set; }
    public string EncodedAbsUrl { get; set; }
    public string FileLeafRef { get; set; }
    public Folder Folder { get; set; }
    public int FileSystemObjectType { get; set; }
    public int Id { get; set; }
    public string ContentTypeId { get; set; }
    public string Title { get; set; }
    public int? ImageWidth { get; set; }
    public int? ImageHeight { get; set; }
    public string ImageCreateDate { get; set; }
    public object Description { get; set; }
    public object Keywords { get; set; }
    public string OData__dlc_DocId { get; set; }     
    public int ID { get; set; }
    public string Created { get; set; }
    public int AuthorId { get; set; }
    public string Modified { get; set; }
    public int EditorId { get; set; }
    public object OData__CopySource { get; set; }
    public int? CheckoutUserId { get; set; }
    public string OData__UIVersionString { get; set; }
    public string GUID { get; set; }
}

//SharePoint Calls
class Program
{
    static void Main()
    {
        string url = "https://sharepoint.wilsonconst.com/";
        string filename = "2010-07-23 13.32.22.jpg";
        string digest = "";
        HttpClient client = new HttpClient(new HttpClientHandler() { UseDefaultCredentials = true });
        client.BaseAddress = new System.Uri(url);
        string cmd = "_api/contextinfo";
        client.DefaultRequestHeaders.Add("Accept", "application/json;odata=verbose");
        client.DefaultRequestHeaders.Add("ContentType", "application/json");
        client.DefaultRequestHeaders.Add("ContentLength", "0");
        StringContent httpContent = new StringContent("");
        HttpResponseMessage response = client.PostAsync(cmd, httpContent).Result;
        if (response.IsSuccessStatusCode)
        {
            string content = response.Content.ReadAsStringAsync().Result;
            RootObject sp = JsonHelper.JsonDeserialize<RootObject>(content);
            digest = sp.d.GetContextWebInformation.FormDigestValue;
        }
        client = new HttpClient(new HttpClientHandler() { UseDefaultCredentials = true });
        client.BaseAddress = new System.Uri(url);
        client.DefaultRequestHeaders.Clear();
        client.DefaultRequestHeaders.Add("Accept", "application/json;odata=verbose");
        client.DefaultRequestHeaders.Add("X-RequestDigest", digest);
        client.DefaultRequestHeaders.Add("X-HTTP-Method", "GET");
        string uri = "_api/web/lists/GetByTitle('Wilson Pictures')/Items?$select=ID,FileLeafRef,EncodedAbsUrl&$filter=FileLeafRef eq '" + filename + "'";
        HttpResponseMessage response2 = client.GetAsync(uri).Result;
        response2.EnsureSuccessStatusCode();
        if (response2.IsSuccessStatusCode)
        {
            string listItems = response2.Content.ReadAsStringAsync().Result;
            RootObject sp = JsonHelper.JsonDeserialize<RootObject>(listItems);
            foreach (Result result in sp.d.results)
            {
                MemoryStream stream = (MemoryStream)client.GetAsync(result.EncodedAbsUrl).Result.Content.ReadAsStreamAsync().Result;
                using(FileStream fileStream = System.IO.File.Create(@"C:\" + result.FileLeafRef))
                {
                    stream.WriteTo(fileStream);
                }
            }
        }
        else
        {
            var content = response.Content.ReadAsStringAsync();
        }
    }

这似乎有很多复杂性，但实际上它使得使用Json对象变得非常简单，只需要设置片刻就可以开始调用自定义对象以轻松操作数据。

Answer 2

假设您要从 SharePoint Online 检索数据，以下示例演示了如何通过WebClient Class使用SharePoint REST接口：

using (var client = new SPRestClient(webUri.ToString()))
{
    client.Credentials = GetCredentials(webUri,userName,password);
    client.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f");
    var data = client.GetJson("/_api/lists/getbytitle('Tasks')/items"); //get list items 
    //print list item's title 
    foreach (var item in data["d"]["results"])
    {
        Console.WriteLine(item["Title"]);
    }
}

，其中

public static SharePointOnlineCredentials GetCredentials(Uri webUri, string userName, string password)
{
    var securePassword = new SecureString();
    foreach (var ch in password) securePassword.AppendChar(ch);
    return  new SharePointOnlineCredentials(userName, securePassword);
}

和

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Http;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace SharePoint.Client
{
    public class SPRestClient : WebClient
    {
        public SPRestClient(string webUri)
        {
            BaseAddress = webUri;
            FormatType = JsonFormatType.Verbose;
        }

        public JObject GetJson(string requestUri)
        {
            return ExecuteJson(requestUri, HttpMethod.Get, null, default(string));
        }

        public JObject ExecuteJson<T>(string requestUri, HttpMethod method, IDictionary<string, string> headers, T data)
        {
            string result;
            var uri = BaseAddress + requestUri;
            if (headers != null)
            {
                foreach (var key in headers.Keys)
                {
                    Headers.Add(key, headers[key]);
                }     
            }

            EnsureRequest(method);
            switch (method.Method)
            {
                case "GET":
                    result = DownloadString(uri);
                    break;
                case "POST":
                    if (data != null)
                    {
                        var payload = JsonConvert.SerializeObject(data);
                        result = UploadString(uri, method.Method, payload);
                    }
                    else
                    {
                        result = UploadString(uri, method.Method);
                    }
                    break;
                default:
                    throw new NotSupportedException(string.Format("Method {0} is not supported", method.Method));
            }
            return JObject.Parse(result);
        }


        private void EnsureRequest(HttpMethod method)
        {
            var mapping = new Dictionary<JsonFormatType, string>();
            mapping[JsonFormatType.Verbose] = "application/json;odata=verbose";
            mapping[JsonFormatType.MinimalMetadata] = "application/json; odata=minimalmetadata";
            mapping[JsonFormatType.NoMetadata] = "application/json; odata=nometadata";
            Headers.Add(HttpRequestHeader.ContentType, mapping[FormatType]);
            Headers.Add(HttpRequestHeader.Accept, mapping[FormatType]);
            if (method == HttpMethod.Post)
            {
                Headers.Add("X-RequestDigest", RequestFormDigest());
            }
        }



        private string RequestFormDigest()
        {
            var endpointUrl = string.Format("{0}/_api/contextinfo", BaseAddress);
            var result = UploadString(endpointUrl, "Post");
            var contentJson = JObject.Parse(result);
            return contentJson["FormDigestValue"].ToString();
        }



        public JsonFormatType FormatType { get; set; }

    }

    public enum JsonFormatType
    {
        Verbose,
        MinimalMetadata,
        NoMetadata
    }
}

SPRestClient.cs

迭代SharePoint 2013 REST API列表项

2 个答案: