title: Pass Selected Dropdown Value to Controller using a Button
body: <p>In the example below when clicking the button the value selected in the dropdownlist should be passed to the controller, but its not.  How can I pass the value?</p>
  
  <p>View:</p>
  
  <pre><code>@model BillingModel
  ...
  &lt;select id="ddl" asp-for="SelectedCompanyID" asp-items="Model.Companies" class="form-control"&gt;&lt;/select&gt;
  
  &lt;a asp-action="Create" asp-controller="Invoice" asp-route-id="@Model.SelectedCompanyID" class="btn btn-primary btn-sm"&gt;&lt;/span&gt; Create Invoice&lt;/a&gt;
  ....
  </code></pre>
  
  <p>Model:</p>
  
  <pre><code>public class BillingModel
  {
      public int SelectedCompanyID { get; set; }       
  
      public SelectList Companies { get; set; }    
  }
  </code></pre>