将图像插入Azure blob - {“错误：内部服务器错误”} MobileInvalidOperationException

我试图将Win 8应用程序中的图像插入Azure blob . 当我尝试这样做时，我遇到了500异常 . 这是我正在使用的课程 -

private MobileServiceCollection<TodoItem, TodoItem> items;
        private IMobileServiceTable<TodoItem> todoTable = App.MobileService.GetTable<TodoItem>();

   [DataContract]
    public class TodoItem
        {

        [DataMember(Name = "id")]
        public int ID { get; set; }

        [DataMember(Name = "text")]
        public string Text { get; set; }



        [DataMember(Name = "containerName")]
        public string ContainerName { get; set; }


        [DataMember(Name = "resourceName")]
        public string ResourceName { get; set; }


        [DataMember(Name = "sasQueryString")]
        public string SasQueryString { get; set; }


        [DataMember(Name = "imageUri")]
        public string ImageUri { get; set; }
        }

The Exception is thrown at line -await todoTable.InsertAsync(todoItem); 此时抛出异常，SASQueryString和ImageUri的值为NULL .

private async void OnTakePhotoClick(object sender, RoutedEventArgs e)
        {
            // Capture a new photo or video from the device.
            CameraCaptureUI cameraCapture = new CameraCaptureUI();
            media = await cameraCapture
                .CaptureFileAsync(CameraCaptureUIMode.PhotoOrVideo);
            TodoItem todoitem = new TodoItem { Text="NA",ContainerName="todoitemimages"};
             InsertTodoItem(todoitem);


        }

private async void InsertTodoItem(TodoItem todoItem)
{
    string errorString = string.Empty;


    if (media != null)
    {
        // Set blob properties of TodoItem.

        todoItem.ResourceName = media.Name;

    }


    // Send the item to be inserted. When blob properties are set this
    // generates an SAS in the response.
    await todoTable.InsertAsync(todoItem);


    // If we have a returned SAS, then upload the blob.
    if (!string.IsNullOrEmpty(todoItem.SasQueryString))
    {
        // Get the new image as a stream.
        using (var fileStream = await media.OpenStreamForReadAsync())
        {
            // Get the URI generated that contains the SAS 
            // and extract the storage credentials.
            StorageCredentials cred = new StorageCredentials(todoItem.SasQueryString);
            var imageUri = new Uri(todoItem.ImageUri);


            // Instantiate a Blob store container based on the info in the returned item.
            CloudBlobContainer container = new CloudBlobContainer(
                new Uri(string.Format("https://{0}/{1}",
                    imageUri.Host, todoItem.ContainerName)), cred);


            // Upload the new image as a BLOB from the stream.
            CloudBlockBlob blobFromSASCredential =
                container.GetBlockBlobReference(todoItem.ResourceName);
            await blobFromSASCredential.UploadFromStreamAsync(fileStream.AsInputStream());
        }
    }


    // Add the new item to the collection.
    items.Add(todoItem);


}

无论如何，我可以解决此异常 . 谢谢 .

这些是例外细节 -
Microsoft.WindowsAzure.MobileServices.MobileServiceInvalidOperationException未处理HResult = -2146233079消息=错误：内部服务器错误源= Microsoft.Threading.Tasks StackTrace：位于Microsoft.Runtime.CompilerServices的Microsoft.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务） . 位于Microsoft.Runtime.CompilerServices.TaskAwaiter.GetResult（）的Microsoft.Runtime.CompilerServices.TaskAwaiter.ValidateEnd（任务任务）中的TaskAwaiter.HandleNonSuccess（任务任务），位于Microsoft.WindowsAzure.MobileServices.MobileServiceTable`1.d_0.MoveNext（） - - 来自抛出异常的先前位置的堆栈跟踪结束---在DeltaVMobile.CrudeStorageScenario.d_22的System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务）的System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）处.MoveNext（）在c：\ Users \〜---从抛出异常的先前位置的堆栈跟踪结束---在System.Runtime.CompilerServices.AsyncM System.Threading.WinRTSynchronizationContext.Invoker.InvokeCore（）中的ethodBuilderCore.b__0（对象状态）---从抛出异常的先前位置开始的堆栈跟踪结束---在系统的System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw（）处.Threading.ExecutionContext.RunInternal（ExecutionContext executionContext，ContextCallback callback，Object state，Boolean preserveSyncCtx）在System.Threading.QueueUserWorkItemCallback.System.Threading的System.Threading.ExecutionContext.Run（ExecutionContext executionContext，ContextCallback callback，Object state，Boolean preserveSyncCtx）中 . System.Threading.ThreadPoolWorkQueue.Dispatch（）中的.IThreadPoolWorkItem.ExecuteWorkItem（）InnerException：