What's the difference between these LINQ queries ?
- by SnAzBaZ
I use LINQ-SQL as my DAL, I then have a project called DB which acts as my BLL. Various applications then access the BLL to read / write data from the SQL Database.
I have these methods in my BLL for one particular table:
public IEnumerable<SystemSalesTaxList> Get_SystemSalesTaxList()
{
return from s in db.SystemSalesTaxLists
select s;
}
public SystemSalesTaxList Get_SystemSalesTaxList(string strSalesTaxID)
{
return Get_SystemSalesTaxList().Where(s => s.SalesTaxID == strSalesTaxID).FirstOrDefault();
}
public SystemSalesTaxList Get_SystemSalesTaxListByZipCode(string strZipCode)
{
return Get_SystemSalesTaxList().Where(s => s.ZipCode == strZipCode).FirstOrDefault();
}
All pretty straight forward I thought.
Get_SystemSalesTaxListByZipCode is always returning a null value though, even when it has a ZIP Code that exists in that table.
If I write the method like this, it returns the row I want:
public SystemSalesTaxList Get_SystemSalesTaxListByZipCode(string strZipCode)
{
var salesTax = from s in db.SystemSalesTaxLists
where s.ZipCode == strZipCode
select s;
return salesTax.FirstOrDefault();
}
Why does the other method not return the same, as the query should be identical ?
Note that, the overloaded Get_SystemSalesTaxList(string strSalesTaxID) returns a record just fine when I give it a valid SalesTaxID.
Is there a more efficient way to write these "helper" type classes ?
Thanks!
