You can left join to a derived table containing the “numbers” (well, strings with a possible numeric representation actually). SELECT d.clientnumber FROM (VALUES (‘00602’), (‘00897’), (‘00940′)) AS n (n) LEFT JOIN dataentry AS de ON de.clientnumber = n.n; That’ll give you as many NULLs as “numbers” in the list that aren’t present in the table … Read more
Solved it. As the comments pointed out, the problem was that I was not accessing ViewController correctly. In order to access my ViewController outside of the ViewController class, I was creating a new instance of it by ViewController(). I solved it by putting the function inside the class and changing ViewController() part to self.ViewController. This … Read more
No, there is not much use. Probably checking the variable being null or not is just as expensive as setting it to null one time too many. If it was a property, with additional logic behind it, it could make sense to test it before, but that should actually be the responsibility of the logic … Read more
What is the cause? Bottom Line You are trying to use something that is null (or Nothing in VB.NET). This means you either set it to null, or you never set it to anything at all. Like anything else, null gets passed around. If it is null in method “A”, it could be that method … Read more