title: How can I add an item from a listBox into a textBox
body: <p><img src="https://i.stack.imgur.com/hW8F0.jpg" alt="enter image description here"></p>
  
  <p>I would like to double click on an item in the list box and have that item show up in the textBox titled File name (please refer  to the picture)</p>
  
  <pre><code>private void listBox1_MouseDoubleClick(object sender, MouseEventArgs e)
  {
    listBox1.Items.Add(textBox2.Text);
  }
  </code></pre>
  
  <p>this code does not work, what am I doing wrong</p>