Difference between a DateTime object I create and DateTime.Now

Question

I'm trying to use the Exchange 2007 API to query calendar availability for a specific user. My sample code is producing the following exception:

The time duration specified for FreeBusyViewOptions.TimeWindow is invalid.

Here's the sample code:

ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);

service.AutodiscoverUrl("email@domain.com");

DateTime startTime = new DateTime(2012, 1, 6, 7, 0, 0);

TimeWindow tw = new TimeWindow(startTime, startTime.AddHours(8));

GetUserAvailabilityResults result = service.GetUserAvailability(new List<AttendeeInfo> { new AttendeeInfo("email@domain.com") }, tw, AvailabilityData.FreeBusyAndSuggestions);

The wierd thing is, if I replace my startTime assignment with the following it works:

DateTime startTime = DateTime.Now;

What's the difference between the DateTime object I created and the object produced by DateTime.Now. I've examined them in detail while debugging and can't find a difference.

Any ideas?

Answer 1

This actually appears to be an issue in the GetUserAvailability method as opposed to any DateTime manipulation.

According to the MSDN documentation :

The GetUserAvailability(Generic ,TimeWindow,AvailabilityData,AvailabilityOptions) method supports only time periods that are a minimum of 24 hours long and that begin and end at 12:00a.m. To restrict the results of the method to a shorter time period, you must filter the results on the client.

Answer 2

I find out that the specified TimeWindow must contain at least one midnight. But I do not know why.

Answer 3

Maybe it has something to do with the difference between your time zone and UTC, producing a negative time window. Try increasing from AddHours(8) to bigger values up to AddHours(24) and see what happens.

Answer 4

Specify the Kind to make it identical to Now:

     DateTime startTime = new DateTime(2012, 1, 6, 7, 0, 0, DateTimeKind.Local);

With some odds that you actually need Utc. Depends on server config probably.

Answer 5

The Kind is different. This may be what it is looking for.

new DateTime(2012, 1, 6, 7, 0, 0)

has a kind of "Unspecified".

While

DateTime.Now

has a Kind of "Local".

Try using ToLocalTime to set the kind to local:

DateTime startTime = new DateTime(2012, 1, 6, 7, 0, 0).ToLocalTime();

Answer 6

Look at the constructors and code for the class DateTime.

All of them alter the private variable:

private ulong dateData;

So all the constructors are the same and DateTime.Now is a public static method that returns an instance of the DateTime class that does the same thing.

The error message stated:

The time duration specified for FreeBusyViewOptions.TimeWindow is invalid.

That is because it is invalid!

You put in a future date, and it most likely checked for that. Try with a current date.