这个get_item到底要如何转换

using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;    using Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder;    using System;    using System.Configuration;    [Assembler(typeof(CacheDependencyAssembler))]    internal class CacheDependencyData : NameTypeConfigurationElement    {        private const string dataBaseProperty = "database";        private const string dataTableProperty = "table";        private static void Settings()        {            new CacheDependencySettings().IsReadOnly();        }        [ConfigurationProperty("database", IsRequired=true)]        public string Database        {            get            {                return (string)  base.get_Item("database");            }            set            {                base.set_Item("database", value);            }        }        [ConfigurationProperty("table", IsRequired=true)]        public string Table        {            get            {                return (string) base.get_Item("table");            }            set            {                base.set_Item("table", value);            }        }    }