N 個 ASP.net DropDownList 無刷新聯動菜單

2019-11-10 19:48:51

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再談 N 個 asp.net DropDownList 無刷新聯動菜單，犧牲N-1個ASPX來實現自動更新機制，避免刷新的閃動！！

以下代碼絕對可以使用，也可以實現多級菜單。。。。

============================

webform1.aspx

private void Page_Load(object sender, System.EventArgs e) { // 在此處放置用戶代碼以初始化頁面 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) { // 在此處放置用戶代碼以初始化頁面 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();　　 } }

---------------------------------

仔細看看``其實完全不用在響應多個DROPLIST的時候犧牲 N-1 個頁面，因為所有的響應都有一個共性，為什么不可以多傳一個值進行判斷響應那一個方法呢？？？

var type ="type1";

oHttpReq.open("post","webform2.aspx?state="+state+"&type="+type, false);

string type = this.Request["type"].ToString();

switch(type)

{

case "type1":

.........................................

}

----------------------------------------------

程序需要做幾處修改：

1、解決drp2、drp3清楚不完全的問題： drp2.innerText =""; drp3.......................

2、

for (var item = items.nextNode();item;item = items.nextNode())　　 {　　　　var city = item.nodeTypedValue;　　　var newOption = document.createElement("OPTION");　　　　newOption.text = city;　　　　newOption.value = city;　　　　drp2.options.add(newOption);　　　　 }　3、如果傳多個值的問題也是一樣``

select t1,t2 from tt

只要多加一個條件就可以解決問題

=======================================================

這個還有很多可以研究的問題``比如刷新后值的問題。。。。。。。。。。。。

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程序演示地址：http://www.718.com.cn/other/Example.aspx

在網上看到了一些無刷新的聯動控件。下下了測試以后，顯示英文和數字可以，但是不可以顯示中文，后來把從網上down下來的文件做了一個翻修改，做了一個省市的聯動控件。給大家共享一下。可以顯示中文了。

<%@ Page language="c#" Codebehind="Example.aspx.cs" AutoEventWireup="false" Inherits="Webs.other.Example" %> <HTML> <HEAD> <title>Example</title> <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1"> <meta name="CODE_LANGUAGE" Content="C#"> <meta name="vs_defaultClientScript" content="Javascript"> <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5"> <script> function load(state){ var drp2 = document.getElementById("DropDownList2"); for (i = drp2.length; i >= 0; i--){ drp2.options.remove(i); } var oHttpReq = new ActiveXObject("MSXML2.XMLHTTP"); var oDoc = new ActiveXObject("MSXML2.DOMDocument"); oHttpReq.open("POST", "getData.aspx?state="+state, false); oHttpReq.send(""); result = oHttpReq.responseText; oDoc.loadXML(result); items1 = oDoc.selectNodes("//CITY/Table/Id"); items2 = oDoc.selectNodes("//CITY/Table/shiname"); var itemsLength=items1.length; 　　for(i=0;i<itemsLength;i++) //將小類的類名和編號賦予DropDownList2 　　{ 　　var newOption = document.createElement("OPTION"); 　　newOption.text=items2[i].text; 　　newOption.value=items1[i].text; 　　drp2.options.add(newOption); 　　} } window.onload = function(){load('1');} </script> </HEAD> <body MS_POSITIONING="FlowLayout"> <form id="Form1" method="post" runat="server"> <asp:DropDownList id="DropDownList1" runat="server"></asp:DropDownList> <asp:DropDownList id="DropDownList2" runat="server"></asp:DropDownList> <asp:TextBox id="TH" runat="server"></asp:TextBox> <asp:Button id="Button1" runat="server" Text="Button"></asp:Button> </form> </body> </HTML>

cs源文件:

using System;using System.Collections;using System.ComponentModel;using System.Data;using System.Drawing;using System.Web;using System.Web.sessionState;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.HtmlControls;using System.Data.SqlClient;

namespace Webs.other{ /// <summary> /// Example 的摘要說明。 /// </summary> public class Example : System.Web.UI.Page { protected System.Web.UI.WebControls.DropDownList DropDownList1; protected System.Web.UI.WebControls.TextBox TH; protected System.Web.UI.WebControls.Button Button1; protected System.Web.UI.WebControls.DropDownList DropDownList2; private void Page_Load(object sender, System.EventArgs e) { // 在此處放置用戶代碼以初始化頁面 if(!this.IsPostBack) { // 建立數據源加載第一個DropDownList，也可以默認加載第二個 SqlConnection con = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings.Get("connStr1")); SqlDataAdapter da = new SqlDataAdapter("select Id,shengname from Province",con); DataSet ds = new DataSet(); da.Fill(ds); this.DropDownList1.DataSource = ds; this.DropDownList1.DataTextField = "shengname"; this.DropDownList1.DataValueField = "Id"; this.DropDownList1.DataBind(); // 這里是綁定客戶端事件，當第一個DropDownList的選項改變時激發下面的事件onchange，這個事件將調用一個客戶端方法load() this.DropDownList1.Attributes.Add("onchange","load(this.options[this.selectedIndex].value)"); } }

#region Web Form Designer generated code override protected void OnInit(EventArgs e) { // // CODEGEN：該調用是 ASP.NET Web 窗體設計器所必需的。 // InitializeComponent(); base.OnInit(e); } /// <summary> /// 設計器支持所需的方法 - 不要使用代碼編輯器修改 /// 此方法的內容。 /// </summary> private void InitializeComponent() { this.Button1.Click += new System.EventHandler(this.Button1_Click); this.Load += new System.EventHandler(this.Page_Load);

} #endregion

private void Button1_Click(object sender, System.EventArgs e) { TH.Text=this.Request.Form["DropDownList2"].ToString(); } }}

getdata源文件

using System;using System.Collections;using System.ComponentModel;using System.Data;using System.Drawing;using System.Web;using System.Web.SessionState;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.HtmlControls;using System.Data.SqlClient;using System.Xml;using System.Configuration;using System.Text;

namespace Webs.other{ /// <summary> /// GetData 的摘要說明。 /// </summary> public class GetData : System.Web.UI.Page { private void Page_Load(object sender, System.EventArgs e) { // 在此處放置用戶代碼以初始化頁面 //Response.Write(Request["state"]); int shengNo=int.Parse(Request["state"].ToString()); SqlConnection con = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings.Get("connStr1")); SqlDataAdapter da = new SqlDataAdapter("select Id,shiname from City where Shengid='"+shengNo+"'",con); DataSet ds = new DataSet("CITY"); da.Fill(ds);

XmlTextWriter writer = new XmlTextWriter(Response.OutputStream,Encoding.UTF8); writer.Formatting = Formatting.Indented; writer.Indentation = 4; writer.IndentChar = ' '; writer.WriteStartDocument(); ds.WriteXml(writer); writer.Flush(); Response.End(); writer.Close(); }

#region Web Form Designer generated code override protected void OnInit(EventArgs e) { // // CODEGEN：該調用是 ASP.NET Web 窗體設計器所必需的。 // InitializeComponent(); base.OnInit(e); } /// <summary> /// 設計器支持所需的方法 - 不要使用代碼編輯器修改 /// 此方法的內容。 /// </summary> private void InitializeComponent() { this.Load += new System.EventHandler(this.Page_Load); } #endregion }}

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ASP.net DropDownList 無刷新聯動！<TITLE>WebForm2</TITLE>

<SCRIPT language='javascript'> function load(){ var drp2 = document.getElementById("DropDownList2"); drp2.innerText=""; for(var i = 0;i<=drp2.options.length -1;i++){ drp2.remove(i); } var drp3 = document.getElementById("DropDownList3"); for(var i = 0;i<=drp3.options.length -1;i++){ drp3.remove(i); } var xmlhttp = new ActiveXObject("MSXML2.XMLHTTP"); var oDoc = new ActiveXObject("MSXML2.DOMDocument"); var state=document.getElementById("DropDownList1").value; xmlhttp.open("POST", "webform1.aspx?id="+state,false); xmlhttp.send(""); var res=oDoc.loadXML(xmlhttp.responseText); var naItems = oDoc.selectNodes("//Market/Table/maName"); var idItems = oDoc.selectNodes("//Market/Table/maId"); var item; var id; for (item = naItems.nextNode(),id=idItems.nextNode(); item&&id; item = naItems.nextNode(),id=idItems.nextNode()){ var nastr = item.nodeTypedValue; var idstr = id.nodeTypedValue; var newOption = document.createElement("OPTION"); newOption.text =nastr; newOption.value = idstr; drp2.options.add(newOption); } load2(); } function load2(){ var drp2 = document.getElementById("DropDownList3"); drp2.innerText=""; for(var i = 0;i<=drp2.options.length -1;i++){ drp2.remove(i); } var xmlhttp = new ActiveXObject("MSXML2.XMLHTTP"); var oDoc = new ActiveXObject("MSXML2.DOMDocument"); var state=document.getElementById("DropDownList2").value; xmlhttp.open("POST", "webform3.aspx?id="+state,false); xmlhttp.send(""); var res=oDoc.loadXML(xmlhttp.responseText); var naItems = oDoc.selectNodes("//Market/Table/maName"); var idItems = oDoc.selectNodes("//Market/Table/maId"); var item; var id; for (item = naItems.nextNode(),id=idItems.nextNode(); item&&id; item = naItems.nextNode(),id=idItems.nextNode()){ var nastr = item.nodeTypedValue; var idstr = id.nodeTypedValue; var newOption = document.createElement("OPTION"); newOption.text =nastr; newOption.value = idstr; drp2.options.add(newOption); } } </SCRIPT> </HEAD> <BODY ms_positioning="GridLayout" onload="load()"> <FORM id="Form1" method="post" runat="server"> <ASP:DROPDOWNLIST id="DropDownList1" runat="server"></ASP:DROPDOWNLIST> <ASP:DROPDOWNLIST id="DropDownList2" runat="server"></ASP:DROPDOWNLIST> <ASP:DROPDOWNLIST id="Dropdownlist3" runat="server"></ASP:DROPDOWNLIST> </FORM> </BODY></HTML>-----------------------namespace dropDown{ /// <summary> /// WebForm2 的摘要說明。 /// </summary> public class WebForm2 : System.Web.UI.Page { protected System.Web.UI.WebControls.DropDownList DropDownList1; protected System.Web.UI.WebControls.DropDownList Dropdownlist3; protected System.Web.UI.WebControls.DropDownList DropDownList2; private void Page_Load(object sender, System.EventArgs e) { // 在此處放置用戶代碼以初始化頁面 if(!this.IsPostBack) { SqlConnection con = new SqlConnection("server=localhost;database=star;uid=sa;pwd="); SqlDataAdapter da = new SqlDataAdapter("select maId,maName from tabMarket where maCls=0",con); DataSet ds = new DataSet(); da.Fill(ds,"op"); this.DropDownList1.DataSource=ds.Tables[0]; this.DropDownList1.DataTextField = "maName"; this.DropDownList1.DataValueField = "maId"; this.DropDownList1.DataBind(); this.DropDownList1.Attributes.Add("onchange","load()"); this.DropDownList2.Attributes.Add("onchange","load2()"); }

}

}}-----------------------public class WebForm1 : System.Web.UI.Page { private void Page_Load(object sender, System.EventArgs e) { // 在此處放置用戶代碼以初始化頁面 // Put user code to initialize the page here //if(this.Request["state"]!=null) //{ string id =this.Request["id"]; SqlConnection con = new SqlConnection("server=localhost;database=star;uid=sa;pwd=;"); SqlDataAdapter da = new SqlDataAdapter("select maName,maId from tabMarket where maParent=@id and maSt=1 ",con); da.SelectCommand.Parameters.Add("@id",id); DataSet ds = new DataSet("Market"); da.Fill(ds); ds.WriteXml(Response.OutputStream); Response.Flush (); Response.End (); //} } }----------------------------- public class WebForm3 : System.Web.UI.Page { private void Page_Load(object sender, System.EventArgs e) { // 在此處放置用戶代碼以初始化頁面 string id =Request["id"]; SqlConnection con = new SqlConnection("server=localhost;database=star;uid=sa;pwd=;"); SqlDataAdapter da = new SqlDataAdapter("select maName,maId from tabMarket where maParent=@id and maSt=1",con); da.SelectCommand.Parameters.Add("@id",id); DataSet ds = new DataSet("Market"); da.Fill(ds); ds.WriteXml(Response.OutputStream); Response.Flush (); Response.End (); } }------------------

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