Re: Nullable Dates
- From: "Ignacio Machin \( .NET/ C# MVP \)" <machin TA laceupsolutions.com>
- Date: Thu, 13 Sep 2007 15:36:27 -0400
Hi,
"Jon Skeet [C# MVP]" <skeet@xxxxxxxxx> wrote in message
news:1189693209.830086.194760@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Sep 13, 3:12 pm, Wannabe <Wann...@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
I have a start and end date in my application. If a user does not know
their
dates yet, I want them, they will be null in the DB and I want them to be
blank in the application. So, I'm trying to figure out how to use a
nullable
date, and want to return it in my method.
I tried to cast the output parameter, but I get a run-time cast error:
return new TimeLine((DateTime?)command.Parameters["@startDate"].Value,
(DateTime?)command.Parameters["@endDate"].Value);
Then I changed to the code to what you see below, and it worked. But I am
wondering is there a better way to do this when working with nullable
dates?
The simplest way would be:
DateTime? startDate = command.Parameters["@startDate"].Value as
DateTime? ;
DateTime? endDate = command.Parameters["@endDate"].Value as
DateTime? ;
That will work, *but* it will give you null for start/end dates which
are neither DBNull nor DateTime. In other words, it will hide the
error. If you want more rigour, I'd write a helper method to convert
object to DateTime, throwing an exception if the parameter is neither
a DateTime nor DBNull.Value.
If the columns in the DB are of DateTime then it will work as expected.
.
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