How can I get SignalR to stop changing my date/time values?

Question

I have a simple class that contains a DateTime property. When I set the value of this property using DateTime.Now() the value is correct. However, when I pass this class object as a parameter via SignalR, on the receiving end SignalR has changed the DateTime so that it no longer matches the original DateTime. How can I get SignalR to stop manipulating my DateTime values? This issue seems to have started with a recent update to the latest SignalR nuget packages.

This seems to be a problem when the hub and the client are in two different time zones. It seems Microsoft is trying to help, by adjusting the date/time to the local time zone, but I want the original value, not the value Microsoft "thinks" I want.

Kiril1512 · Answer 1 · 2020-10-15T14:39:08.980

When you want two systems to communicate with each other I would recommend using always the DateTime in UTC for various reasons. In your case you have two options here:

1 - Send the date as string string date = DateTime.Now.ToString(CultureInfo.InvariantCulture); so on the client side you just need to parse the datetime like DateTime.Parse(date, CultureInfo.InvariantCulture);.

2 - Send the date in UTC like DateTime.UtcNow; so event if the SignalR tries to change the date, it will have the DateTime.Kind as UTC. In this case or you will get the current date correctly, or you just adjust on the client side to the local time like receivedDate.ToLocalTime();

score 0 · Answer 2 · answered Nov 10 '22 at 14:13

This one was a real head scratcher as I had the exact same issue. The client was storing the correct time but by the time it hit the Hub... it had changed. I'm really glad you posted this as I wouldn't have imagined this issue being possible. @Kiril1512 posted the correct resolution. In my case I used his second option as I didn't want to change my model... although simply converting to a string would have been simpler. While I did follow his suggestion and convert everything to DateTime.UtcNow()... I am thinking this was unnecessary as I noticed even previously stored dates converted correctly. This makes me think that either this isn't necessary to do, or dates are converted to Utc when they hit the Hub automatically which may be what the issue was to begin with?

Either way I posted this as I discovered that converting this date back to Local time was a little more involved. Here is how I ended up doing the conversion which resolved this issue for me that I gathered from this resource:

DateTime convertedDate = DateTime.SpecifyKind(
                        DateTime.Parse(msg.CreatedOn.ToString()),
                        DateTimeKind.Utc);
                        var kind = convertedDate.Kind;
                        DateTime dt = convertedDate.ToLocalTime();

How can I get SignalR to stop changing my date/time values?

2 Answers2