title: error: Use of unassigned local variable
body: <p>I have this method:</p>
  <pre><code>public static void Add(int _Serial, string _Name, long? _number1, long? _number2)
  {
      // ...
  }
  </code></pre>
  <p>and use this code for send date to method:</p>
  <pre><code>long? _num1;
  long? _num2;
  if (txtNumber1.Text != null &amp;&amp; txtNumber1.Text != &quot;&quot;)
  {
      _num1= long.Parse(txtNumber1.Text);
  }
  if (txtNumber2.Text != null &amp;&amp; txtNumber2.Text != &quot;&quot;)
  {
      _num2= long.Parse(txtNumber2.Text);
  }
  Add(22, &quot;Kati&quot;, _num1, _num2)
  </code></pre>
  <p>but Error <code>_num1</code> &amp; <code>_num2</code> in <code>Add(...)</code>.</p>
  <p>Error:</p>
  <blockquote>
  <p>Use of unassigned local variable '_num1'</p>
  <p>Use of unassigned local variable '_num2'</p>
  </blockquote>