Question

有人可以请另一只眼睛吗？我试图在显示之前验证斑点图像是否存在。这可能需要1-4秒。我的JS看起来像这样：

   var url = '/api/blob/ValidateBlobExists?id=' + blobImage;
        $.getJSON(url,
            function(json) {
                console.log("success");
            })
            .done(function () {
                console.log("second success");
                 exists = data;
                if (exists) {
                    console.log("exists'");
                $('#imgPhotograph').hide().attr('src', blobImage).fadeIn();
            } else {
                $('#imgPhotograph').attr('src', '../Images/NoPhotoFound.jpg');
            }
        });

api看起来像这样..请不要判断..它的vb，因为它必须是。

   Public Function ValidateBlobExists(id As String) As JsonResult(Of Boolean)
    dim result = CDNHelper.BlobExists(id) 'this could take ~5 seconds
    Return Json(Of Boolean)(result)
End Function

底层方法如下：

  public static bool BlobExists(string filename)
    {
        try
            {
                var sw = new Stopwatch();
                sw.Start();
                do
                {
                    if (client.AssertBlobExists(filename).Result) // <-- this is a wrapper to query the azure blob
                     return true;

                        System.Threading.Thread.Sleep(500); //no reason to hammer the service

                } while (sw.ElapsedMilliseconds < 8000);

            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                throw;
            }
        }

        return false;
    }

问题出在我的控制台输出中，我什至无法获得“成功”。似乎getJson（）只是不愿意等待8秒钟过去再继续。任何想法都值得赞赏。

Answer 1

问题是我的API响应签名未装饰为“异步”。即使我打电话给.result，它也变得混乱了。对我来说，解决方案是按以下方式修改我的代码

 Public Async Function ValidateBlobExists(id As String) As Task(Of JsonResult(Of Boolean))
         result = await CDNHelper.BlobExists(id, "ioc")
         return result
End function

和

public static async Task<bool> BlobExists()
{
return client postasync wrapper
}

.getJSON响应未发生

1 个答案: