how store Dynamic dropdown all value (Selected/Unselected) C#, ASP.NET
<p>I am binding a Dropdown dynamically. Now i need to catch all value (selected &amp; Unselected) to pass through in a function. </p>

<p>This in my dropdown code. </p>

<pre><code>  &lt;asp:DropDownList ID="ddlVoucherTypes" cssClass="form-control" runat="server" OnSelectedIndexChanged="RedefineOldVoucherHistory"
                                AutoPostBack="true"&gt;
                            &lt;/asp:DropDownList&gt;
</code></pre>

<p>How can i get all value with coma (,) separated ? like this (13,23,45,21) </p>