public class NumericUpDownTypeEditor : UITypeEditor
   {
      public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
      {
         if (context == null || context.Instance == null)
            return base.GetEditStyle(context);
         return context.PropertyDescriptor.IsReadOnly ? UITypeEditorEditStyle.None : UITypeEditorEditStyle.DropDown;
      }

      public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
      {
         try
         {
            if (context == null || context.Instance == null || provider == null)
               return value;
            
            //use IWindowsFormsEditorService object to display a control in the dropdown area  
            IWindowsFormsEditorService frmsvr = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));
            if (frmsvr == null)
               return value;

           
            if (attr != null)
            {
               NumericUpDown nmr = new NumericUpDown();
               frmsvr.DropDownControl(nmr);
               context.OnComponentChanged();
               return Convert.ChangeType(nmr.Value, context.PropertyDescriptor.PropertyType);
            }
         }
         catch { }
         return value;
      }
   }