i want to validate the combobox of content page whether it is selected on submitting the Master Page's Button

pirvate bool vcf()
{
    object[] parameters = new object[] { };

        CallContentFunction(StringConstants.validCompulsoryFields);//from here control goes to following, within the same Page i.e. Master Page
}


private object CallContentFunction(string methodName, params object[] parameters)
    {
        try
        {
                Type contentType = this.Page.GetType();
                System.Reflection.MethodInfo mi = contentType.GetMethod(methodName);
                if (mi == null) return null;
                mi.Invoke(this.Page, parameters);//Consider mi!=null her & then   from here control goes to content page's ValidCompulsoryFields()
                return mi;
        }
        catch (Exception exception)
        {
           throw exception;
        }
    }

public bool ValidCompulsoryFields()
   {
       //Check for State
       {
           try
           {
               if (StateName1.Text == string.Empty || StateName1.Text == StringConstants.select ||
                   StateName1.SelectedValue.ToString() == StringConstants.select)   //if condition goes true,
               {

                   throw new Exception(ErrorConstants.selectTheState);
               }

               return true;
           }
           catch (Exception exception)
           {
               MessageBox.Show(exception.Message);
               StateName1.Focus();
               throw exception;
               // return false;

           }

       }
   }<-------- At this point I'm getting an error message as, "Exception was Unhandelled by User Code"".