What datatype should I use in C# to work with the SQL Server uniqueidentifier.
Do I need any conversions etc ?
3 Answers
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.
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.
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