一款异步加载下拉框插件

一款不错的基于JQuery的auto-complete插件，这款插件最大的好处就是我们能够得到{value, text}结构的数据，这与传统的下拉框很相似，非常适合用于项目开发。

生成后的Html页面代码

<div style=" 200px;" class="dhx_combo_box ">
<input type="text" autocomplete="off" class="dhx_combo_input" style=" 181px;">
<input type="hidden" name="LocalityObject" value="14523">
<input type="hidden" name="LocalityObject_new_value" value="false">
<img class="dhx_combo_img" src="http://www.cnblogs.com/Scripts/DHTMLX/codebase/imgs/combo_select.gif">
</div>

以下是基于MVC的一个例子

前台调用

<script type="text/javascript">

    $(function() {
        window.dhx_globalImgPath = "http://www.cnblogs.com/Scripts/DHTMLX/codebase/imgs/";
        var z = new dhtmlXCombo("localobj", "LocalityObject", 200, 22);
        z.enableFilteringMode(true, "http://www.cnblogs.com/Community/AsynchronousLocality", true, true);
    });
</script>

后台代码

public ActionResult AsynchronousLocality()
        {
            XmlDocument xmldoc = new XmlDocument();
            var content = BuildXML();
            try
            {
                xmldoc.LoadXml(content);
            }
            catch(Exception e) {
                
            }
           
            return new XmlResult(xmldoc);
        }

private string BuildXML()
        {
            string qstring = Request.QueryString["mask"].SafeString();
            string start = Request.QueryString["pos"].SafeString(); 

            StringBuilder sb = new StringBuilder();

            sb.Append("<?xml version=\"1.0\" ?>");
            sb.AppendFormat("<complete{0}>", start.SafeInt().Equals(0)? string.Empty : " add=\"true\"");
            if (!string.IsNullOrEmpty(qstring))
            {
                var communities = Service.ListLocalityByName(qstring);

                for (var i = 0; i < communities.Count; i++)
                {
                    if (i > 50) break;
                    sb.AppendFormat("<option value=\"{0}\">{1}</option>", communities[i].Id, communities[i].LocalityName);
                }
            }
            sb.Append("</complete>");

            return sb.ToString().Replace("&", "&amp;");
        }

XmlResult类

public class XmlResult : ActionResult
    {
        private object objectToSerialize;

        /// <summary>
        /// Initializes a new instance of the <see cref="XmlResult"/> class.
        /// </summary>
        /// <param name="objectToSerialize">The object to serialize to XML.</param>
        public XmlResult(object objectToSerialize)
        {
            this.objectToSerialize = objectToSerialize;
        }

        /// <summary>
        /// Gets the object to be serialized to XML.
        /// </summary>
        public object ObjectToSerialize
        {
            get { return this.objectToSerialize; }
        }

        /// <summary>
        /// Serialises the object that was passed into the constructor to XML and writes the corresponding XML to the result stream.
        /// </summary>
        /// <param name="context">The controller context for the current request.</param>
        public override void ExecuteResult(ControllerContext context)
        {
            if (this.objectToSerialize != null)
            {
                context.HttpContext.Response.Clear();
                var xs = new System.Xml.Serialization.XmlSerializer(this.objectToSerialize.GetType());
                context.HttpContext.Response.ContentType = "text/xml";
                xs.Serialize(context.HttpContext.Response.Output, this.objectToSerialize);
            }
        }
    }