title: Check that integer type belongs to enum member
body: <p>I want to check that some integer type belongs to (an) enumeration member.</p>
  
  <p>For Example,</p>
  
  <pre><code>public enum Enum1
  {
      member1 = 4,
  
      member2 = 5,
  
      member3 = 9,
  
      member4 = 0
  }
  </code></pre>
  
  <p>Enum1 e1 = (Enum1)4 gives me member1</p>
  
  <p>Enum1 e2 = (Enum1)10 gives me nothing and I want to check it.</p>