I'm attempting to query my db using Enumerable.Contains
inside a SqlExpressionVisitor.Where
clause. When the lambda is compiled, I'm getting a null reference exception.
When the visitor makes it to foreach (Object e in inArgs)
(currently line 1067) inside SqlExpressionVisitor.VisitArrayMethodCall
, it chokes because inArgs
is null. The following is my sample that causes the error. I don't understand lambdas/expressions well enough to know why this is happening.
So my questions is, am I not using the Where
clause properly or is this a bug?
class Program
{
static void Main(string[] args)
{
var connectionFactory = new OrmLiteConnectionFactory(@"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|Database1.mdf;Integrated Security=True;User Instance=True", SqlServerDialect.Provider);
SetupDb(connectionFactory);
using (var db = connectionFactory.OpenDbConnection())
{
var numbersToSelect = new int[2] { 1, 2 };
db.Select<SomeObject>(e => e.Where(o => numbersToSelect.Contains(o.Number)));
}
}
static void SetupDb(IDbConnectionFactory connectionFactory)
{
using (var db = connectionFactory.OpenDbConnection())
{
db.DropTable<SomeObject>();
db.CreateTable<SomeObject>();
db.Insert(new SomeObject { Number = 1 });
db.Insert(new SomeObject { Number = 2 });
db.Insert(new SomeObject { Number = 3 });
db.Insert(new SomeObject { Number = 4 });
db.Insert(new SomeObject { Number = 5 });
}
}
}
class SomeObject
{
public int Number { get; set; }
}
After a little more digging, it turns out calling the compiled method is returning an int[]
which causes the cast to object[]
to be null. Casting to IEnumerable
fixes my specific issue.
Changed
var getter = lambda.Compile();
var inArgs = getter() as object[];
to
var getter = lambda.Compile();
var inArgs = getter() as IEnumerable;
Not sure what sort of implications this has though (if any). Still looking for some guidance.
Instead of using Contains, use Sql.In
db.Select<SomeObject>(e => e.Where(o => Sql.In(o.Number,numbersToSelect)));
Turns out it was a bug. It's been fixed for the sqlite visitor and the sql visitor as of commit 9f0b0e8 Thanks @mythz.
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