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bernie2436
bernie2436

Reputation: 23941

how do I check for underlying null value using linq to sql?

I know that if you query a linq-to-sql record (ie row in DB/object) with a null field, then linq to SQL will allow you to access the null value without a null reference exception, like this: Dim myValue as String = myRecord.Nullfield.

But I WANT to query records where the field in the underlying DB is null.

How do I do that with LINQ? 

(From l In myDB.myTable Where l.Program.Equals(DBNull.Value) Select l).Count //Unexpected type code: DBNull

What is the syntax that I am looking for?

Upvotes: 0

Views: 1200

Answers (2)

Alexander
Alexander

Reputation: 4173

See null semantics mismatching article on MSDN. Generally, you can use either

(From l In myDB.myTable Where l.Program.Equals(null) Select l).Count

or

(From l In myDB.myTable Where l.Program == null Select l).Count

Upvotes: 0

usr
usr

Reputation: 171236

Use == null (or whatever the VB.NET equivalent is). No more DBNull. Yay!

Upvotes: 2

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