title: Why do we use += when adding an event to a button?
body: <p>I am new to ASP.NET and I have a question about adding a event handler to a button (html server control) when the page is loaded.</p>
  
  <p>This code is in C#:</p>
  
  <pre><code>protected void Page_Load(object sender, EventArgs e)
  {
      Submit.ServerClick+=Submit_ServerClick;
  }
  </code></pre>
  
  <p>Here, my question is why do we need to add += and what is its significance?</p>