.NET 4.0: New API

.NET 4.0 adds several new methods. 
1) Enum.HasFlag  checks  whether a flag field present in the enum instance.

[Flags]

public enum PizzaToppings

{

Onions = 1,

Mushrooms = 2,

Chicken = 4

}

PizzaToppings myToppings = PizzaToppings.Onions |

PizzaToppings.Mushrooms;

Assert.IsFalse( myToppings.HasFlag(PizzaToppings.Chicken),

"Chicken is not expected"); 

2) String.IsNullOrWhiteSpace can be useful when whitespace condition needs to be checked along with Empty, and Null conditions.

[Test]

public void TestIsNullOrWhiteSpace()

{

string s = " \t ";

Assert.IsTrue( string.IsNullOrWhiteSpace(s),

"tabbed white spaces");

Assert.IsTrue(string.IsNullOrWhiteSpace(null), "Null");

Assert.IsTrue(string.IsNullOrWhiteSpace(""), "Empty");

Assert.IsTrue(string.IsNullOrEmpty(" \t ".Trim()));

}