- Posted by Ian Suttle on December 22, 2007
- Filed under .Net Framework
Tonight I'm playing around with LINQ to SQL using the AdventureWorks database. I'm going to load a product from the Product table given the ProductID, therefore loading a single product. Simple right? There are a couple of was to construct a LINQ statement to retrieve a record:
LINQ Query
public Product GetProduct(int productID)
{
AdventureWorksDBDataContext db = new AdventureWorksDBDataContext();
Product product = (from p in db.Products
where p.ProductID == productID
select p).Single();
return product;
}
Using a Lambda expression
public Product GetProduct(int productID)
{
AdventureWorksDBDataContext db = new AdventureWorksDBDataContext();
Product product = db.Products.Single(p => p.ProductID == productID);
return product;
}
If you notice I'm using the Single() extension method, which will absolutely do the job... when the record exists. The gotcha is if the record doesn't exist an exception is thrown. Instead of using the Single() method, use SingleOrDefault(). This is one you'll learn the hard way... I did. Here's a sample using the Lambda expression without worrying about an exception when the record is missing.
Using a Lambda expression with SingleOrDefault
public Product GetProduct(int productID)
{
AdventureWorksDBDataContext db = new AdventureWorksDBDataContext();
Product product = db.Products.SingleOrDefault(p => p.ProductID == productID);
return product;
}
