/// <summary>
        /// 为 <see cref="HtmlHelper"/> 对象扩展 numberbox 元素。
        /// </summary>
        /// <typeparam name="TModel">数据模型类型。</typeparam>
        /// <typeparam name="TProperty">绑定的属性的类型。</typeparam>
        /// <param name="htmlHelper"></param>
        /// <param name="expression">指定绑定属性的表达式。</param>
        /// <param name="settings">参数选项。</param>
        /// <returns></returns>
        public static ExtendHtmlString NumberBox <TModel, TProperty>(this HtmlHelper <TModel> htmlHelper, Expression <Func <TModel, TProperty> > expression, NumberBoxSettings settings = null)
        {
            settings = settings ?? new NumberBoxSettings();

            var metadata     = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
            var propertyName = metadata.PropertyName;

            settings.Bind(typeof(TModel), propertyName);

            var builder = new EasyUITagBuilder("input", "easyui-numberbox", settings);

            builder.MergeAttribute("name", propertyName);
            builder.MergeAttribute("data-options", SettingsSerializer.Serialize(settings));
            builder.AddCssClass("form-input");
            builder.GenerateId("txt" + propertyName);
            return(new ExtendHtmlString(builder));
        }
        /// <summary>
        /// 为 <see cref="HtmlHelper"/> 对象扩展 numberbox 元素。
        /// </summary>
        /// <param name="htmlHelper"></param>
        /// <param name="exp">属性名或使用 txt 作为前缀的 ID 名称。</param>
        /// <param name="settings">参数选项。</param>
        /// <returns></returns>
        public static ExtendHtmlString NumberBox(this HtmlHelper htmlHelper, string exp, NumberBoxSettings settings = null)
        {
            settings = settings ?? new NumberBoxSettings();

            var builder = new EasyUITagBuilder("input", "easyui-numberbox", settings);

            builder.MergeAttribute("name", exp);
            builder.MergeAttribute("data-options", SettingsSerializer.Serialize(settings));
            builder.AddCssClass("form-input");
            builder.GenerateId("txt" + exp);
            return(new ExtendHtmlString(builder));
        }