title: ASP.NET - Validating Control Inside UserControl
body: <p>I have a wrapper UserControl control around a DropDownList for managing language specific translation on the DropDownList values.</p>
  
  <p>I also have a required field validator that is requried for the inner dropdownlist.</p>
  
  <p>How can I expose this control via the usercontrol to allow validation?</p>
  
  <p>The error I am currently getting is as follows:</p>
  
  <pre><code>... cannot be validated. at System.Web.UI.WebControls.BaseValidator.CheckControlValidationProperty(String name, String propertyName)
        at System.Web.UI.WebControls.BaseValidator.ControlPropertiesValid()
  </code></pre>
  
  <p>Edit:
  I'm now using...</p>
  
  <pre><code>[ValidationPropertyAttribute("SelectedValue")]
  </code></pre>
  
  <p>.... With</p>
  
  <pre><code>public string SelectedValue
  {
      get { return cboI18nItems.SelectedValue; }
  }
  </code></pre>
  
  <p>Which is now working if I check the IsValid property of the page on postback.</p>