A Better string.IsNullOrEmpty and more...

Submitted by brian on Sat, 06/20/2009 - 1:40am.

Here's a better version of string.IsNullOrEmpty(). Why is it better you say? Well my friend, this one checks the string for spaces... It also returns a positive statement (true if it is NOT null and NOT empty)

    public static class Extensions
    {
        public static bool IsSafe(this string s)
        {
            return (s != null && s.Trim().Length > 0);
        }
    }

And some unit tests...

       [Test]
        public void IsSafeStringTest()
        {
            string cheese = "is good";
            Assert.IsTrue(cheese.IsSafe());
            cheese = "";
            Assert.IsFalse(cheese.IsSafe());
            cheese = "   ";
            Assert.IsFalse(cheese.IsSafe());
            cheese = null;
            Assert.IsFalse(cheese.IsSafe());
 
            //-------------------------------
            cheese = "yum";
            Assert.IsFalse(string.IsNullOrEmpty(cheese));
            cheese = "";
            Assert.IsTrue(string.IsNullOrEmpty(cheese));
            cheese = null;
            Assert.IsTrue(string.IsNullOrEmpty(cheese));
 
            // rut roh... 
            // string.IsNullOrEmpty() and spaces are not nice together.
            cheese = "   ";
            // should be true!
            Assert.IsFalse(string.IsNullOrEmpty(cheese));
 
 
        }

While the following might be nice, we know that we can't do it because of the null reference exception we might get (if cheese were to be null)...

string.IsNullOrEmpty(cheese.Trim());

Anyway, while we're doing some extension methods, here's a similarly named one I also use when working with generic lists.

        public static bool IsSafe<T>(this List<T> t)
        {
            return (t != null && t.Count() > 0);
        }

And some unit tests...

       [Test]
        public void IsSafeListTest()
        {
 
            var objectList = new List<object>();
            Assert.IsFalse(objectList.IsSafe());
 
            List<int> intList = null;
            Assert.IsFalse(intList.IsSafe());
 
            var stringList = new List<string>(){"cheese","beer","nachos"};
            Assert.IsTrue(stringList.IsSafe());
        }