title: Select multiple value in ListBox using ASP.NET and C#
body: <p>Why "SelectedValue" selects only the first value in my multiple selection mode ?</p>
  
  <pre><code>&lt;dt&gt;Tags:&lt;/dt&gt;&lt;dd&gt;
  &lt;asp:ListBox ID="ListTag" runat="server" SelectionMode="Multiple"
      DataSourceID="SqlDataSourceTag" DataTextField="tag_name" 
      DataValueField="tag_id"&gt;
  &lt;/asp:ListBox&gt;
  &lt;asp:SqlDataSource ID="SqlDataSourceTag" runat="server" 
      ConnectionString="&lt;%$ ConnectionStrings:db_cc %&gt;"&gt;
  &lt;/asp:SqlDataSource&gt;
  &lt;/dd&gt;
  </code></pre>
  
  <blockquote>
  <pre><code>ListTag.SelectedValue = "Tag1"; &lt;-- only this is selects
  ListTag.SelectedValue = "Tag2";
  </code></pre>
  </blockquote>