Question

我试图在C＃应用程序中多次调用Sharepoint API，并将返回的结果存储到List中，如下所示

  private async Task<List<sDTO.RootObject>> getfromSharepoint()
    {
       List<SharepointDTO.RootObject> returnObj = new List<SharepointDTO.RootObject>();
       var result = new UpdateCoreStrains.SharepointDTO.RootObject();
        ......
        // Calling GET Sharepoint Site
        try
        {
            for (int i = 0; i < 10000; i = i + 5000)
            {
                SP_StrainCodes = "GetByTitle('S%20Codes')/items?$skiptoken=Paged=TRUE%26p_ID=" + i + "&$top=1";
                core_URL = BaseURL_SP + SP_StrainCodes;

                var response = client_sharePoint.GetAsync(core_URL).Result;
                var responsedata = await response.Content.ReadAsStringAsync();
                 result = JsonConvert.DeserializeObject<sDTO.RootObject>(responsedata);
                    if (result.d.Next == null)
                        continue;

                }
                returnObj.Add(result);
            }
            return returnObj;
        }

现在我要在其他函数中调用getfromSharepoint（），并且要遍历List来验证数据

    public List<numberList>  getListFromSharepoint()
    {
        List<umberList> nums = new List<numberList>();
        try
        {

            Task<List<sDTO.RootObject>> sharepointList = getfromSharepoint();

            foreach(sDTO retSharepointobj in sharepointList)
            {

                if (retSharepointobj == null ||
                    retSharepointobj.Id == 0 ||
                    retSharepointobj.Result.
                    retSharepointobj.Result == null ||
                    retSharepointobj.Result.d == null ||
                    retSharepointobj.Result.d.results == null ||
                    retSharepointobj.Result.d.results.Count == 0
                    )
                {
                    return nums;  // count = 0, return an empty list
                }

但是我收到类似

的错误

foreach statement cannot operate on variables of type 'Task<List<SharepointDTO.RootObject>>' because 'Task<List<SharepointDTO.RootObject>>' does not contain a public definition for 'GetEnumerator'如何遍历>

Answer 1

尝试将getListFromSharepoint方法设置为async。

 public async Task<List<numberList>> getListFromSharepoint()
    {
        List<umberList> nums = new List<numberList>();
        try
        {
            //Here we use an await to get result from getfromSharepoint() method call.
            List<sDTO.RootObject> sharepointList = await getfromSharepoint();

            foreach (sDTO retSharepointobj in sharepointList)
            {
                //your rest of code is same here
            }

编辑：

从其他函数中调用getListFromSharepoint方法为

List<numberList> result = await getListFromSharepoint();

OR

您可以简单地使用Result中的getfromSharepoint。

List<sDTO.RootObject> sharepointList = await getfromSharepoint().Result;

Answer 2

Ths：Task<List<sDTO.RootObject>> sharepointList = getfromSharepoint();正在调用async方法，该方法不会立即返回。您的代码应如下所示：

List<sDTO.RootObject> sharepointList = getfromSharepoint().Result;

Answer 3

此处您要遍历sharepointList类型为Task的项目，该项目不包含“ GetEnumerator”的公共定义（如错误消息所述）。但是您可以迭代Task的结果，因为Task的结果为RootObject的集合。如果您要遍历List<sDTO.RootObject>中的sharepointList，则应使用：

foreach (sDTO.RootObject retSharepointobj in sharepointList.Result)
{
   // here each retSharepointobj  of type RootObject 
   // code here
}

在类型'Task <list <sharepointdto.rootobject >>的变量上使用foreach语句

3 个答案: