title: Use DropDownCheckBoxes in c#
body: <p>I use the <a href="https://www.nuget.org/packages/DropDownCheckBoxes" rel="nofollow noreferrer">DropDownCheckBoxes</a> for populate this <strong>List Item</strong>:</p>
  <p><a href="https://i.stack.imgur.com/rW6cz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rW6cz.png" alt="enter image description here" /></a></p>
  <p>From this <strong>List Item</strong> you can select recipients of an email message, but only the first selected value name is the <strong>&quot;To&quot;</strong> address destination.</p>
  <p>The following selected value name are <strong>&quot;CC&quot;</strong> address destination.</p>
  <p>My problem if select <em>foo</em> for <strong>&quot;To&quot;</strong> and <em>foo1</em> for <strong>&quot;CC&quot;</strong> :</p>
  <p><a href="https://i.stack.imgur.com/l7SDa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/l7SDa.png" alt="enter image description here" /></a></p>
  <p>The output is correct :</p>
  <p><a href="https://i.stack.imgur.com/90HMV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/90HMV.png" alt="enter image description here" /></a></p>
  <p>But if try select <em>foo1</em> for <strong>&quot;To&quot;</strong> and <em>foo</em> for <strong>&quot;CC&quot;</strong> I need this output:</p>
  <pre><code>TO : foo1@email.com
  CC : foo@email.com 
  </code></pre>
  <p>Instead of :</p>
  <p><a href="https://i.stack.imgur.com/90HMV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/90HMV.png" alt="enter image description here" /></a></p>
  <p>How to do resolve this ?</p>
  <p>Thank you in advance for any help, really appreciated.</p>
  <pre><code>string sEmail = string.Empty;
  foreach (ListItem item in myListItem.Items)
  {
      if (item.Selected)
      {
          sEmail += item.Value + &quot;; &quot;;
      }
  }
  </code></pre>
  <h1>Edit01</h1>
  <p>Now I use two separate dropdown lists: one for <strong>&quot;to&quot;</strong> other for <strong>&quot;cc&quot;</strong>.</p>
  <p>But if possible disabled all values of <strong>&quot;to&quot;</strong> first dropdownlist when is selected one value ?</p>