title: Append String to Label
body: <p>I want to append text to label on <code>CheckChanged</code> Event, I Have tried the following code but it does not seem to work. Could you suggest me what to change?
  here is my code</p>
  
  <pre><code>protected void CheckBox2_CheckedChanged(object sender, EventArgs e)
  {
      CheckBox2.Visible = false;
      DropDownList2.Visible = true;
      CheckBox3.Visible = true;
      Label2.Text += "-" + DropDownList2.SelectedValue;
  }
  
  protected void CheckBox3_CheckedChanged(object sender, EventArgs e)
  {
      CheckBox3.Visible = false;
      DropDownList3.Visible = true;
      CheckBox4.Visible = true;
      Label2.Text += "-" + DropDownList3.SelectedValue;
  }
  </code></pre>