CreateIfNotExists throwing ArgumentNullExecption

问题

var blobClient = storageAccount.CreateCloudBlobClient();
cont_ref = blobClient.GetContainerReference("foo");
cont_ref.CreateIfNotExists();

The code was working perfectly until recentliy. Now it's throwing an ArgumentNullException.

Q The examples I've seen, demonstrate it like that. What's wrong?

Update The stacktrace contained in the exception reads at System.Enum.TryParseEnum(Type enumType, String value, Boolean ignoreCase, EnumResult& parseResult)

来源：https://stackoverflow.com/questions/43803222/createifnotexists-throwing-argumentnullexecption