Final answer:
The primary difference between IsNullOrEmpty and IsNullOrWhiteSpace in C# is that IsNullOrEmpty checks if a string is either null or empty, while IsNullOrWhiteSpace also checks for strings that contain only whitespace characters.
Step-by-step explanation:
The difference between IsNullOrEmpty and IsNullOrWhiteSpace in C# lies in the level of string validation each provides.
IsNullOrEmpty is a method that checks whether a given string is null or an Empty string (""). This means that if a string has any characters in it, including whitespaces, it will return false.
On the other hand, IsNullOrWhiteSpace checks for a broader set of conditions. It returns true if the string is null, empty, or consists only of whitespace characters such as spaces, tabs or newlines. Hence, it is a stricter check compared to IsNullOrEmpty because it also considers strings filled with invisible characters like spaces as not meaningful.
For instance, if you have a string variable str with a value of a single space (" "), IsNullOrEmpty(str) will return false, while IsNullOrWhiteSpace(str) will return true.