Question

请看下面的代码。

public static class DbModel
{
        public static readonly int TableID = 0;

        static DbModel()
        {
            DbModel.PodID = FetchTableID().PodID;
        }

        public static Pod FetchTableID()
        {
            Pod result = null;
            try
            {                
        //Control never comes back from this line.  What am I missing?
                var searchResult = apiPod.SearchTableAsync(1).Result;
                result = searchResult.First();
            }
            catch (Exception ex)
            {
                Helpers.TraceException(PageName,"FEtchPodID","Unable to fetch PodID",ex);
            }
            return result;
        }
}

SearchTableAsync的签名如下所示

public async Task<List<Pod>> SearchTableAsync(int i)
        {
            try
            {
                using (var client = new HttpClient())
                {
                    //deleted - connecting to server, constructing query string etc.

                    var response = await client.GetAsync(ApiBaseUrl + "api/Pod/Search" + queryString);
                    if (response.IsSuccessStatusCode)
                    {
                        var podList = await response.Content.ReadAsAsync<List<Pod>>();
                        return podList;
                    }
                    else
                    {
                        //log error
                    }
                }
            }
            catch (Exception ex)
            {
                Logger.TraceError(null, ex);
            }
            return null;
        }

调用SearchTableAsync永远不会返回。我错过了什么吗？或者因为我从静态构造函数中调用它？

Answer 1

问题可能是由于使用了Task.Result属性。这是一个阻止属性，可能会导致deadlock。您只需await将返回结果的任务，但您需要制作方法async。

    public static async Pod FetchTableID()
    {
        Pod result = null;
        try
        {                
            var searchResult = await apiPod.SearchTableAsync(1);
            result = searchResult.First();
        }
        catch (Exception ex)
        {
            Helpers.TraceException(PageName,"FEtchPodID","Unable to fetch PodID",ex);
        }
        return result;
    }

Answer 2

searchResult = apiPod.SearchTableAsync（1）.excute.get;

使用此代替

var searchResult = apiPod.SearchTableAsync（1）.Result;

Answer 3

This帖子解释了为何阻止它。干杯，与Hemant

异步调用永远不会返回

3 个答案: