title: System.Web.Mvc.HtmlHelper' does not contain a definition for CheckBox
body: <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
  using System.Web.Mvc;
  using System.Text;
  namespace secondMvc.MyControls
  {
      public static class CheckBoxList
      {
          public static MvcHtmlString CheckListBox(this HtmlHelper helper, string Name, Dictionary&lt;Int32, string&gt; citiesList, bool IsVertical, string cssClass)
          {
              StringBuilder sb = new StringBuilder();
  
              sb.Append(string.Format("&lt;div &gt;"));
              foreach (var item in citiesList)
              {
  
  
                  sb.Append(helper.CheckBox(item.Value, true, new { @class = cssClass, value = item.Key }));
                  sb.Append(helper.Label("RadioButtonItems", item.Value));
                  sb.Append("&amp;nbsp;");
                  if (IsVertical) sb.Append("&lt;br&gt;");
  
              }
              sb.Append("&lt;/div&gt; ");
              return MvcHtmlString.Create(sb.ToString());
          }
      }
  }
  </code></pre>
  
  <p><code>System.Web.Mvc.HtmlHelper</code>'<code>does not contain a definition for</code>CheckBox<code>and no extension method</code>'CheckBox'<code>accepting a first argument of type</code>'System.Web.Mvc.HtmlHelper'` could be found (are you missing a using directive or an assembly reference?)   </p>
  
  <p>i change web.config like this:</p>
  
  <pre><code>&lt;configuration&gt;
  
      &lt;appSettings&gt;
  
      &lt;/appSettings&gt;
  
      &lt;connectionStrings&gt;
  
      &lt;/connectionStrings&gt;
    &lt;pages&gt;
      &lt;namespaces&gt;
  
        &lt;add namespace="secondMvc.MyControls"/&gt;
      &lt;/namespaces&gt;
    &lt;/pages&gt;
  
    &lt;system.web&gt;
      &lt;compilation&gt;
        &lt;assemblies&gt;
        &lt;add assembly="secondMvc.MyControls" /&gt;
        &lt;/assemblies&gt;
      &lt;/compilation&gt;
    &lt;/system.web&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>but i have same error.
  any idea?</p>