Question

.net 为什么DropDownList下拉只能取到第一个值呢，无论选那个值最终的结果都是第一个

姓名：<asp:DropDownList ID="myname" runat="server" > </asp:DropDownList> using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Web.Security;using System.Collections;using System.Configuration;using System.Data;using System.Linq;using System.Xml.Linq;using System.IO;using System.Data.SqlClient;public partial class Teacher_Pra_Progress : System.Web.UI.Page{ public string sql, id; public DBConnection conn = new DBConnection(); protected void Page_Load(object sender, EventArgs e) { //在页面首次执行才执行if (!IsPostBack)避免页面回发 if (!IsPostBack) { MynameDataBind(); GetUser(); } } //姓名的动态绑定，根据教师的职工号 public void MynameDataBind() { sql = "Select S_name,S_id from S_Teacher Where T_id='" + Session["user"].ToString() + "'"; SqlDataReader dr = conn.ExecuteReader(sql); this.myname.DataSource = dr;//设置数据源，用于填充控件中的项的值列表 this.myname.DataTextField = "S_name";//下拉显示出来的值 this.myname.DataValueField = "S_id";//取到的值 this.myname.DataBind();//将控件及其所有子控件绑定到指定的数据源 dr.Close(); } //动态获取要查看的学生信息 public void GetUser() { this.id = this.myname.SelectedValue.ToString().Trim(); //this.myname.SelectedValue;//获得ddlBrand.DataValueField的值,即S_id。 //this.myname.SelectedItem.Text;//获得ddlBrand.DataTextField的值，即S_name。 Label1.Text = id; Session["sid"] = id; sql = "Select * from User_Student Where S_id='" + Session["sid"] + "'"; SqlDataReader dr = conn.ExecuteReader(sql); if (dr.Read()) { sno.Text = dr["S_id"].ToString(); sname.Text = dr["S_name"].ToString(); ssdept.Text = dr["S_sdept"].ToString(); smajor.Text = dr["S_major"].ToString(); sclass.Text = dr["S_class"].ToString(); } dr.Close(); }}

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Answer 1

onselectedindexchanged看一下你的数据源，你用ajax获取吧，动态执行，会达到你所需要的效果，写个程序处理文件，ashx文件，局部加载

Answer 2

设置autoback属性为true试试

追问

设置过了，一样，可能onselectedindexchanged写错了，不大会写这个方法

追答

onselectedindexchanged里面注意要写

if (!IsPostBack)
{｝

Answer 3

设置autoback属性为true

Answer 4

需要调试下看看吧！~