title: C# Object Reference : How can i do it?
body: <p>This is class <strong>Test</strong></p>
  
  <pre><code>public class Test
  {
      public string mystr;
  }
  </code></pre>
  
  <p>And i call it from method :</p>
  
  <pre><code>  string my = "ABC";
    Test test = new Test();
    test.mystr = my;
    test.mystr = "";
  </code></pre>
  
  <p>Result of a bit code above are : <code>my = "ABC"</code> and <code>test.mystr = ""</code></p>
  
  <p>How can I set <code>my</code> to empty string <code>""</code> when I change <code>test.mystr  = ""</code>?</p>