What datatype should I use in C# to work with the SQL Server uniqueidentifier.
Do I need any conversions etc ?
- 4This lists the equivalent .net types for all sql data types: msdn.microsoft.com/en-us/library/ms131092.aspxuser121301– user1213012010-01-27 17:31:51 +00:00Commented Jan 27, 2010 at 17:31
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3 Answers
No conversions needed.
1 Comment
Justin Niessner
Check this link if you have any other parameter data type mapping issues: msdn.microsoft.com/en-us/library/ms131092.aspx
System.Guid
When reading nullable Uniqueidentifier columns from your database, be sure to check if the value is null before attempting to assign to a Guid instance, as Guids are not nullable. For example:
... /// using recordset rs // generates exception if rs["my_guid"] is null Guid g = (Guid)rs["my_guid"]; // returns Guid.Empty {0000000-.....} if db value is null Guid g = (Guid)(rs["my_guid"] ?? Guid.Empty); etc.
3 Comments
Daniel Brückner
Just use Guid? A.K.A. Nullable<Guid> and you can assign null.
3Dave
That doesn't always work - ie, you'll have to wind up converting it to a non-nullable Guid at some point if you're passing to code that doesn't allow nullable Guids.
Kiquenet
Any full source code sample using Guid? and considering DBNull != null?
If you are getting the value from a SQLDataReader, make sure to check it against DBNull before you try to use it. Sometimes the value can be interpreted as a string as well, so you need to type New Guid(rs["my_guid"]) to make sure you have a guid to use in your code.
