title: Confused about Enum Data Type Definition?
body: <p>As I know I can define a new Enum DataFormat at the my project Class, 
  Suppose, I don't do that, I can reference the DataFormat from the 3rd-Party DLL.
  Then I can use the Enum DataFormat from the metadata of 3rd-Party DLL too.</p>
  
  <p>What's the difference? And are the any guideline to define A new Enum DataFormat ? Thanks.</p>
  
  <pre><code>    public enum DataFormat
      {
          SECS = 0,
          S2_L = 4,
          S2_B = 8,
          S2_BOOLEAN = 12,
          S2_A = 16,
          S2_J = 20,
          S2_U1 = 24,
          S2_U2 = 25,
          S2_U4 = 26,
          S2_U8 = 27,
          S2_I1 = 28,
          S2_I2 = 29,
          S2_I4 = 30,
          S2_I8 = 31,
          S2_F4 = 34,
          S2_F8 = 35,
          S2_STRING = 36,
      }
  }
  </code></pre>