private void filed_changed(object sender, SelectionChangedEventArgs e)
        {
            var controlop  = new ControlAndOperator();
            var pinfo      = field_cb.SelectedValue as PropertyInfo;
            var ctlcontext = new FormItemContext(_type, pinfo);

            controlop.InputControl = InputControlBuilder.CreateControl(ctlcontext);
            if (pinfo.PropertyType.Name.Equals("string", StringComparison.OrdinalIgnoreCase))
            {
                controlop.UseStringOperator = true;
            }
            else
            {
                controlop.UseNumberOperator = true;
            }

            if (CreateControlCallback != null)
            {
                controlop = CreateControlCallback(ctlcontext, controlop);
            }

            _bindobject = Activator.CreateInstance(_type);
            controlop.InputControl.DataContext = _bindobject;
            input_br.Child = controlop.InputControl;

            operator_cb.ItemsSource = null;
            if (controlop.UseStringOperator)
            {
                operator_cb.ItemsSource = EnumNameValuePair.EnumToList(typeof(StringOperator));
            }
            else if (controlop.UseNumberOperator)
            {
                operator_cb.ItemsSource = EnumNameValuePair.EnumToList(typeof(NumberOperator));
            }

            operator_cb.SelectedIndex = 0;

            if (pinfo.PropertyType.IsEnum)
            {
                operator_cb.IsEnabled = false;
            }
            else
            {
                operator_cb.IsEnabled = true;
            }
        }
        private void filed_changed(object sender, SelectionChangedEventArgs e)
        {
            var controlop = new ControlAndOperator();
            var pinfo=field_cb.SelectedValue as PropertyInfo;
            var ctlcontext = new FormItemContext(_type, pinfo);
            controlop.InputControl= InputControlBuilder.CreateControl(ctlcontext);
            if (pinfo.PropertyType.Name.Equals("string", StringComparison.OrdinalIgnoreCase))
            {
                controlop.UseStringOperator = true;
            }
            else
                controlop.UseNumberOperator = true;

            if (CreateControlCallback != null)
                controlop = CreateControlCallback(ctlcontext, controlop);

            _bindobject = Activator.CreateInstance(_type);
            controlop.InputControl.DataContext = _bindobject;
            input_br.Child = controlop.InputControl;

            operator_cb.ItemsSource = null;
            if (controlop.UseStringOperator)
                operator_cb.ItemsSource = EnumNameValuePair.EnumToList(typeof(StringOperator));
            else if (controlop.UseNumberOperator)
                operator_cb.ItemsSource = EnumNameValuePair.EnumToList(typeof(NumberOperator));

            operator_cb.SelectedIndex = 0;

            if (pinfo.PropertyType.IsEnum)
            {
                operator_cb.IsEnabled = false;
            }else
            {
                operator_cb.IsEnabled = true;
            }
        }