string.IsNullOrEmpty() vs string.NotNullOrEmpty()

Question

I\'m curious if any developers use string.IsNullOrEmpty() more often with a negative than with a positive

e.g.

if (!string.IsNullOrEmpty())

Answer 1

I prefer the extension method:

public static class StringExtensions
{
    public static bool IsNullOrEmpty(this string value)
    {
        return string.IsNullOrEmpty(value);
    }
}

I find it reads better to say:

if(myValue.IsNullOrEmpty())

or

if(!myValue.IsNullOrEmpty())

Answer 2

C# naming conventions dictate that your expressions should be in the positive such as "Is..." and not "IsNot..."

EDIT: Typically, I use it when doing error checking and input validation at the beginning of a method and raise an exception if the parameter is null or empty.

if (string.IsNullOrEmpty(myParameter))
{
throw new ....
}