title: What is code between '[]' and what does it do?
body: <p>I've been learning C# for a while. Wrote a few programs etc. I have not dealt with advanced concepts, but when studying other peoples' code I notice that there are certain lines of code that I do not understand why they are there. In the example I understand I know it is importing a DLL but am not sure what this line of code is called? Is it a statement? Where can I learn more about them?</p>
  
  <p>Trying to learn about something without knowing what it is called is impossible :)</p>
  
  <p>Example:</p>
  
  <pre><code>[DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
  static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
  [DllImport("user32.dll", EntryPoint = "SendMessage", SetLastError = true)]
  static extern IntPtr SendMessage(IntPtr hWnd, Int32 Msg, IntPtr wParam, IntPtr lParam);
  </code></pre>