再谈 N 个 ASP.net DropDownList 无刷新联动菜单,牺牲N-1个ASPX来实现自动更新机制,避免刷新的闪动!!
以下代码绝对可以使用,也可以实现多级菜单。。。。
<script language="javascript"> function load(state) { var drp2 = document.getElementById("DropDownList2"); for(var i=0;i<=drp2.options.length-1;i++) { drp2.remove(i); } var oHttpReq = new ActiveXObject("MSXML2.XMLHTTP"); //发送请求 var oDoc = new ActiveXObject("MSXML2.DOMDocument"); //响应结果 var state=document.getElementById("DropDownList1").value; oHttpReq.open("post","webform2.aspx?state="+state, false); oHttpReq.send(""); result = oHttpReq.responseText; oDoc.loadXML(result);
// items = oDoc.selectNodes("//CITY/Table"); items = oDoc.selectNodes("//address/Table"); for (var item = items.nextNode();item;item = items.nextNode()) { var city = item.selectSingleNode("//address").nodeTypedValue; var newOption = document.createElement("OPTION"); newOption.text = city; newOption.value = city; drp2.options.add(newOption); } } </script>
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webform1.aspx
private void Page_Load(object sender, System.EventArgs e) { // 在此处放置用户代码以初始化页面 if(!IsPostBack) { SqlConnection con = new SqlConnection("packet size=4096;user id=sa;data source=SERVER;persist security info=False;initial catalog=pubs"); SqlDataAdapter da = new SqlDataAdapter("select state from authors group by state",con); DataSet ds = new DataSet("State"); da.Fill(ds); this.DropDownList1.DataSource = ds.Tables[0]; this.DropDownList1.DataTextField = "state"; this.DropDownList1.DataValueField = "state"; this.DropDownList1.DataBind(); this.DropDownList1.Attributes.Add("onchange","load()"); //DropDownList1. }
}
webform2.aspx
private void Page_Load(object sender, System.EventArgs e) { // 在此处放置用户代码以初始化页面 if(this.Request["state"]!=null) { string state = this.Request["state"].ToString(); SqlConnection con = new SqlConnection("packet size=4096;user id=sa;data source=SERVER;persist security info=False;initial catalog=pubs"); SqlDataAdapter da = new SqlDataAdapter("select address from authors where state = ''''"+state+"''''",con); DataSet ds = new DataSet("address"); da.Fill(ds); XmlTextWriter writer = new XmlTextWriter(Response.OutputStream, Response.ContentEncoding); writer.Formatting = Formatting.Indented; writer.Indentation = 4; writer.IndentChar = '''' ''''; ds.WriteXml(writer); writer.Flush(); Response.End(); writer.Close(); } }