title: How can I convert textbox value to double in c#?
body: <p>I am new to c# and using windows forms. 
  I have 2 textboxes <code>textbox1</code> and <code>textbox2</code>.</p>
  
  <p>Lets say textbox1 has a value of 22, when I click on textbox2, the value in textbox1 should change to double (22.00).</p>
  
  <pre><code>textbox1.text = "22";
  private void textBox2_MouseClick(object sender, MouseEventArgs e)
  {
      // convert the value in textbox1 to double .
  }
  </code></pre>