绑定下拉菜单的通用方法

        /// <summary>
        /// 下拉菜单绑定
        /// </summary>
        /// <param name="ddl">下拉菜单ID</param>
        /// <param name="list">数据源</param>
        /// <param name="textField">文本</param>
        /// <param name="valueField">值</param>
        /// <param name="defaultValue">首项默认值</param>
        protected void DropDownListBind(DropDownList ddl, object list , string textField, string valueField, string defaultValue)
        {
            ddl.DataSource = list;
            ddl.DataTextField = textField;
            ddl.DataValueField = valueField;
            ddl.DataBind();

            if (!String.IsNullOrEmpty(defaultValue))
                ddl.Items.Insert(0, new ListItem(defaultValue, "0"));
        }