What is a NullReferenceException, and how do I fix it?
I have some code and when it executes, it throws a NullReferenceException, saying: Object reference not set to an instance of an object. What does this mean, and what can I do to fix …
What is a NullPointerException, and how do I fix it?
What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? What methods/tools can be used to determine the cause so that you stop the exception from …
How can I check for an undefined or null variable in JavaScript?
96 Checking null with normal equality will also return true for undefined. if (window.variable == null) alert('variable is null or undefined');
How do I check if a Sql server string is null or empty
Right that is worth noting, but this works as a shortcut because the comparison makes the null coalesce to the correct boolean so this wouldn't work for the inverse comparison of LEN …
What is the purpose of null? - Stack Overflow
Feb 25, 2009 · Null: The Billion Dollar Mistake. Tony Hoare: I call it my billion-dollar mistake. It was the invention of the null reference in 1965. At that time, I was designing the first …
What is the difference between "x is null" and "x == null"?
Nov 18, 2016 · 173 Overloaded equals operator There is in fact a difference in semantics between the two comparisons when you are comparing null with a type that has overloaded …
c# - What does null! statement mean? - Stack Overflow
Feb 16, 2019 · It can be used on a type to control Nullability, it is then called the "Null Forgiving Operator". Basically, null! applies the ! operator to the value null. This overrides the nullability …
Representing null in JSON - Stack Overflow
What is the preferred method for returning null values in JSON? Is there a different preference for primitives? For example, if my object on the server has an Integer called …
The difference between `typeof x !== "undefined"` and `x != null`
But in this case only null and undefined are loosely equal to each other, therefore != null will return false for either of the two value, true for everything else. typeof input !== "undefined" Here the …
JavaScript checking for null vs. undefined and difference between ...
Feb 24, 2011 · How do I check a variable if it's null or undefined and what is the difference between the null and undefined? What is the difference between == and === (it's hard to …