how to extract value from LINQ query?

  • Thread starter Thread starter SftwDude
  • Start date Start date
S

SftwDude

Is it possible to extract a single value from the results of a LINQ query
with out iterating over the results.

For example I have a table in SQL Server:

tblExample
Type int <--this is a key field
Descr nvarchar(5)

I would like to get the description (Descr) field something like this in C#:

string Description = from Example in db.tblExample where Example.Type = 1
select Example.Descr;

I know this query returns an IQueryable and the above query won't compile
because of type mismatch. Is there a way to get the string from the database
field using a LINQ query?

Thanks
 
Thanks for Patrice's prompt reply.

Hello SftwDude

I agree with Patrice. Single () function returns only one element from
query, and throws an exception if sequence contains more than one element
or empty. Alternative way, you can use First() function to return the
first element from the query when there are more than one element in your
sequence.
For example:

string Description = (from Example in db.tblExample
where Example.Type = 1
select Example.Descr).Frist();

Hope this helps, If you have any more concern or there is anything unclear,
please feel free to let us know. We are glad to assist you.

Have a great day,
Best regards,
Wen Yuan

Microsoft Online Community Support
Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
(e-mail address removed).
==================================================
Get notification to my posts through email? Please refer to
http://msdn.microsoft.com/subscriptions/managednewsgroups/default.aspx#notif
ications.

Note: The MSDN Managed Newsgroup support offering is for non-urgent issues
where an initial response from the community or a Microsoft Support
Engineer within 1 business day is acceptable. Please note that each follow
up response may take approximately 2 business days as the support
professional working with you may need further investigation to reach the
most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
project analysis and dump analysis issues. Issues of this nature are best
handled working with a dedicated Microsoft Support Engineer by contacting
Microsoft Customer Support Services (CSS) at
http://msdn.microsoft.com/subscriptions/support/default.aspx.
==================================================
This posting is provided "AS IS" with no warranties, and confers no rights.
 
Error 1 Cannot convert method group 'First' to non-delegate type 'string'.
Did you intend to invoke the method?

This is the error I receive if I try to do what you have suggested...

Kartik
 
Hello Kartik

Could you please paste your LINQ Query?

I think we needn't call toString() function after First(). Frist() function
returns the fist element in query. However, in this case, each element
turned by Linq Query is String type.

Hope this helps,
Best regards,
Wen Yuan

Microsoft Online Community Support
Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
(e-mail address removed).
==================================================
This posting is provided "AS IS" with no warranties, and confers no rights.
 
Back
Top