Problem using string.IsnullorEmpty in linq query

Question

I have a linq query in which i want to include those record which are not null or empty in database field but when i use string.isNullorEmpty it gives me error. How can i achieve this task my query is

from post in PostIdPostMeta1
join pstmt in postrepository.GetAllPostMetas() on post.int_PostId equals pstmt.int_PostId
where string.IsNullOrEmpty(pstmt.vcr_MetaValue) == false
select post

If i change string.IsNullOrEmpty(pstmt.vcr_MetaValue) == false to pstmt.vcr_MetaValue != string.Empty it give me SQL Server does not handle comparison of NText, Text, Xml, or Image data types error

Boolean IsNullOrEmpty(System.String)' has no supported translation to SQL — Fraz Sundal
– Fraz Sundal, Commented May 4, 2011 at 10:03

Jon Skeet · Accepted Answer · 2011-05-04 10:58:56Z

5

Well, the error message seems reasonably clear - I suspect that if you want to be able to do this, you'll need to use an nvarchar field instead of text / ntext.

EDIT: It's not just the database field that needs to be the right type; it's also the type that LINQ to SQL thinks it is. You need to keep your DBML in sync with your actual database schema.

edited May 4, 2011 at 10:58

answered May 4, 2011 at 10:37

Jon Skeet

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2 Comments

Jon Skeet Over a year ago

@Fraz: Are you absolutely sure? The error message strongly suggests it's not. Was it text / ntext at some earlier time? Perhaps you need to update the LINQ to SQL entities...

Fraz Sundal Over a year ago

Yes my mistake i forgot to update the DBML after changing the data type in database

Anders Fjeldstad · Accepted Answer · 2011-05-04 10:09:22Z

2

Have you tried replacing

where string.IsNullOrEmpty(pstmt.vcr_MetaValue)

with

where pstmt.vcr_MetaValue != null && pstmt.vcr_MetaValue != string.Empty

?

answered May 4, 2011 at 10:09

Anders Fjeldstad

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1 Comment

Fraz Sundal Over a year ago

it give me SQL Server does not handle comparison of NText, Text, Xml, or Image data types error

pabdulin · Accepted Answer · 2011-05-04 10:08:10Z

1

Try this code:

from post in PostIdPostMeta1
join pstmt in postrepository.GetAllPostMetas() on post.int_PostId equals pstmt.int_PostId
where ((pstmt.vcr_MetaValue != "") && (pstmt.vcr_MetaValue != null))
select post

answered May 4, 2011 at 10:08

pabdulin

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Comments

Ramazan Binarbasi · Accepted Answer · 2013-11-20 10:55:36Z

1

If DB field is NTEXT, You can check if field is not like empty string. Here's an example;

from post in PostIdPostMeta1
join pstmt in postrepository.GetAllPostMetas() on post.int_PostId equals pstmt.int_PostId
where !SqlMethods.Like(pstmt.vcr_MetaValue, "")
select post

answered Nov 20, 2013 at 10:55

Ramazan Binarbasi

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1 Comment

Ramazan Binarbasi Over a year ago

Like method does not check null fields, so I've removed null check from example.

Andrew Hanlon · Accepted Answer · 2011-05-04 10:09:26Z

0

I'm not sure about which linq provider you are using, and from a quick google-ing it seems that IsNullOrEmpty is not universally supported. The answers that popped up while typing this look correct.

answered May 4, 2011 at 10:09

Andrew Hanlon

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