问题描述
js省市联动的select下拉框，怎么在aspx下面得到选中的值为什么我得的空详解。。。
解决方案
解决方案二：
在onselectchange事件中将里面的值写给一个服务器控件。然后取得时候取这个服务器控件的值就可以了
解决方案三：
用requst.form来取值看.我以前也碰到过类似的问题。后来干脆我把它换成了html控件了，然后取值的时候用request.form，赋值的时候用变量<%=%>来赋值
解决方案四：
document.all["控件名"].options[document.all["控件名"].selectedIndex].text
解决方案五：
或者用Request.Form["下拉框的name"]
解决方案六：
前台:<HTML><HEAD><title>XmlHttp实现无刷新三联动下拉框</title><metaname="GENERATOR"Content="MicrosoftVisualStudio.NET7.1"><metaname="CODE_LANGUAGE"Content="C#"><metaname="vs_defaultClientScript"content="JavaScript"><metaname="vs_targetSchema"content="http://schemas.microsoft.com/intellisense/ie5"></HEAD><body><formid="Form1"method="post"runat="server"><INPUTstyle="Z-INDEX:102;LEFT:448px;WIDTH:56px;POSITION:absolute;TOP:8px;HEIGHT:24px"onclick="getData();"type="button"value="test"><asp:TextBoxid="TextBox1"style="Z-INDEX:101;LEFT:16px;POSITION:absolute;TOP:8px"runat="server"Width="424px"></asp:TextBox><asp:DropDownListid="DropDownList2"runat="server"style="Z-INDEX:103;LEFT:176px;POSITION:absolute;TOP:48px"></asp:DropDownList><asp:DropDownListid="DropDownList1"runat="server"style="Z-INDEX:104;LEFT:16px;POSITION:absolute;TOP:48px"></asp:DropDownList><asp:DropDownListid="DropDownList3"runat="server"style="Z-INDEX:105;LEFT:296px;POSITION:absolute;TOP:48px"></asp:DropDownList><SCRIPTLANGUAGE="JavaScript"><!--//以XML求取DropDownList2的数据functionXmlPost2(obj){//debugger; varsvalue=obj.value; varwebFileUrl="?provinceid="+svalue; varresult=""; varxmlHttp=newActiveXObject("MSXML2.XMLHTTP"); xmlHttp.open("POST",webFileUrl,false); xmlHttp.send(""); result=xmlHttp.responseText; if(result!="") { //debugger; document.all("DropDownList2").length=0; varpiArray=result.split(","); for(vari=0;i<piArray.length;i++) { varary1=piArray[i].toString().split("|"); document.all("DropDownList2").options.add(newOption(ary1[1].toString(),ary1[0].toString())); } } else { alert(result); }}//以XML求取DropDownList3的数据functionXmlPost3(obj){ varsvalue=obj.value; varwebFileUrl="?cityid="+svalue; varresult=""; varxmlHttp=newActiveXObject("MSXML2.XMLHTTP"); xmlHttp.open("POST",webFileUrl,false); xmlHttp.send(""); result=xmlHttp.responseText; if(result!="") { document.all("DropDownList3").length=0; varpiArray=result.split(","); for(vari=0;i<piArray.length;i++) { varary1=piArray[i].toString().split("|"); document.all("DropDownList3").options.add(newOption(ary1[1].toString(),ary1[0].toString())); } } else { alert(result); }}functiongetData(){varprovince=document.getElementById("DropDownList1");varpindex=province.selectedIndex;varpValue=province.options[pindex].value;varpText=province.options[pindex].text;varcity=document.getElementById("DropDownList2");varcindex=city.selectedIndex;varcValue=city.options[cindex].value;varcText=city.options[cindex].text;vararea=document.getElementById("DropDownList3");varaindex=area.selectedIndex;varaValue=area.options[aindex].value;varaText=area.options[aindex].text;vartxt=document.getElementById("TextBox1");document.getElementById("<%=TextBox1.ClientID%>").innerText="省:"+pValue+"|"+pText+"市:"+cValue+"|"+cText+"区:"+aValue+"|"+aText;}//--></SCRIPT></form></body></HTML>后台publicstaticstringConnectionString=System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"];#regionGetDataSetpublicstaticDataSetGetDataSet(stringsql){SqlDataAdaptersda=newSqlDataAdapter(sql,ConnectionString);DataSetds=newDataSet();sda.Fill(ds);returnds;}#endregion#regionpropertyprivatestringprovinceid{get{if(ViewState["provinceid"]!=null&&ViewState["provinceid"].ToString()!=""){returnViewState["provinceid"].ToString();}else{if(Request["provinceid"]!=null&&Request["provinceid"].ToString()!=""){returnRequest["provinceid"];}else{return"";}}}set{ViewState["provinceid"]=value;}}privatestringcityid{get{if(ViewState["cityid"]!=null&&ViewState["cityid"].ToString()!=""){returnViewState["cityid"].ToString();}else{if(Request["cityid"]!=null&&Request["cityid"].ToString()!=""){returnRequest["cityid"];}else{return"";}}}set{ViewState["provinceid"]=value;}}#endregion#regionPage_LoadprotectedvoidPage_Load(objectsender,System.EventArgse){if(!this.IsPostBack) { this.down1_bind();this.DropDownList1.Attributes.Add("onchange","XmlPost2(this);");this.DropDownList2.Attributes.Add("onchange","XmlPost3(this);"); } if(provinceid!="") { this.down2_bind(provinceid); }if(cityid!="") { this.down3_bind(cityid); }}#endregion#regiondown2_bindprivatevoiddown2_bind(stringid){ stringmystr=""; stringsql="selectcityID,cityfromcitywherefather='"+id+"'"; DataSetds=GetDataSet(sql); if(ds.Tables[0].Rows.Count!=0) { for(inti=0;i<ds.Tables[0].Rows.Count;i++) { mystr+=","+ds.Tables[0].Rows[i][0].ToString()+"|"+ds.Tables[0].Rows[i][1].ToString(); } mystr=mystr.Substring(1); } this.Response.Write(mystr); this.Response.End();}#endregion#regiondown3_bindprivatevoiddown3_bind(stringid){ stringmystr=""; stringsql="selectareaID,areafromareawherefather='"+id+"'"; DataSetds=GetDataSet(sql); if(ds.Tables[0].Rows.Count!=0) { for(inti=0;i<ds.Tables[0].Rows.Count;i++) { mystr+=","+ds.Tables[0].Rows[i][0].ToString()+"|"+ds.Tables[0].Rows[i][1].ToString(); } mystr=mystr.Substring(1); } this.Response.Write(mystr); this.Response.End();}#endregion#regiondown1_bindprivatevoiddown1_bind(){ stringsql="selectprovinceID,provincefromprovince"; DataSetds=GetDataSet(sql); this.DropDownList1.DataSource=ds; this.DropDownList1.DataValueField="provinceID"; this.DropDownList1.DataTextField="province"; this.DropDownList1.DataBind(); }#endregion
解决方案七：
up
解决方案八：
onselectchange="方法"autopostback=true;
解决方案九：
将autopostback设置为true,使它可以自动处理就可以实现了。