dropdownlist 选取值问题 请教！

Question

我写了个页面 .cs文件的代码是这样写的
    private string myConnectionString = ConfigurationManager.ConnectionStrings["yxwhConnectionString"].ConnectionString;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (权限判断)
        {
            this.Panel1.Visible = true;
            this.Panel2.Visible = false;
            this.Panel3.Visible = false;
            this.Panel4.Visible = false;
            dpl1build();
        }
        else
        {
            this.Panel1.Visible = false;
            this.Panel2.Visible = true;
            this.Panel3.Visible = false;
            this.Panel4.Visible = false;
        }
       
       
    }
    private void dpl1build()
    {
       
            SqlConnection myconnection = new SqlConnection(myConnectionString);
            string cmdtext = "select * from dqfl";
            SqlDataAdapter myda = new SqlDataAdapter(cmdtext, myconnection);
            try
            {
                ///打开连接
                myconnection.Open();                DataSet ds = new DataSet("UserDataSet");                ///填充DataSet
                myda.Fill(ds, "Users");
                DropDownList1.DataSource = ds;
                DropDownList1.DataTextField = "dq";
                DropDownList1.DataValueField = "dq";
                DropDownList1.DataBind();
            }
            catch (SqlException sqlex)
            {
                ///显示链接错误的消息
                Response.Write(sqlex.Message + "<br>");
            }
            finally
            {
                ///关闭数据库的链接
                myconnection.Close();
            }
        
    }
    private void dpl2build()
    {
        SqlConnection myconnection = new SqlConnection(myConnectionString);
        string cmdtext = "select * from sbfl";
        SqlDataAdapter myda = new SqlDataAdapter(cmdtext, myconnection);
        try
        {
            ///打开连接
            myconnection.Open();            DataSet ds = new DataSet("sbdataset");            ///填充DataSet
            myda.Fill(ds, "sbdata");
            DropDownList2.DataSource = ds;
            DropDownList2.DataTextField = "sbn";
            DropDownList2.DataValueField = "sbn";
            DropDownList2.DataBind();
        }
        catch (SqlException sqlex)
        {
            ///显示链接错误的消息
            Response.Write(sqlex.Message + "<br>");
        }
        finally
        {
            ///关闭数据库的链接
            myconnection.Close();
        }    }
    private void dpl3build()
    {
       
        SqlConnection myconnection = new SqlConnection(myConnectionString);
        string cmdtext = "select jgn,jgm from jn";
        SqlDataAdapter myda = new SqlDataAdapter(cmdtext, myconnection);
        try
        {
            ///打开连接
            myconnection.Open();            DataSet ds = new DataSet("jgdataset");            ///填充DataSet
            myda.Fill(ds, "jgdata");
            DropDownList3.DataSource = ds;
            DropDownList3.DataTextField = "jgn";
            DropDownList3.DataValueField = "jgn";
            DropDownList3.DataBind();
        }
        catch (SqlException sqlex)
        {
            ///显示链接错误的消息
            Response.Write(sqlex.Message + "<br>");
        }
        finally
        {
            ///关闭数据库的链接
            myconnection.Close();
        }    }    protected void Button2_Click(object sender, EventArgs e)
    {
        this.Panel1.Visible = false;
        this.Panel2.Visible = false;
        this.Panel3.Visible = false;
        this.Panel4.Visible =true;
        string sbb = DropDownList2.SelectedValue;
        string dqq=DropDownList1.SelectedValue;
        Label2.Text = dqq;
        Label3.Text = sbb;
        dpl3build();
    }    protected void Button1_Click1(object sender, EventArgs e)
    {
        this.Panel1.Visible = false;
        this.Panel2.Visible = false;
        this.Panel3.Visible = true;
        this.Panel4.Visible = false;
        string dqq = DropDownList1.SelectedValue;
        Label1.Text = dqq;
        dpl2build();
    }
    protected void Button3_Click(object sender, EventArgs e)
    {
        this.Panel1.Visible = false;
        this.Panel2.Visible = false;
        this.Panel3.Visible = false;
        this.Panel4.Visible = true;
        string sbb = DropDownList2.SelectedValue;
        string dqq = DropDownList1.SelectedValue;
        Label2.Text = dqq;
        Label3.Text = sbb;
    }
}测试中也没发现什么打错误 却发现一个很奇怪的问题。当我点击Button1后 声明的dqq传递的值是 dropdownlist1的数据源中的第一个值 选择其他的值 Button1点击够传递的仍然是第一个，二其他几个Button点击后却传递的是所选择的值 请教下这是什么原因引起的 该怎么解决？

Answer 1

aspx页是这样写的<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="gzdj.aspx.cs" Inherits="gzdj" Title="%>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
    <asp:Panel ID="Panel1" runat="server" Height="50px" Width="100%">
        <table border="0" cellpadding="0" cellspacing="0" style="width: 100%">
            <tr>
                <td colspan="2" style="text-align: center">
                    <br />
                    故障登记<br />
                </td>
            </tr>
            <tr>
                <td style="width: 300px; height: 36px;">
                    请选择发生的地区：<asp:DropDownList ID="DropDownList1" runat="server" EnableTheming="False">
                    </asp:DropDownList>
                    <asp:Button ID="Button1" runat="server" Text="确定" OnClick="Button1_Click1" /></td>
                <td style="width: 100px; height: 36px;">
                    </td>
            </tr>
            <tr>
                <td style="width: 100px">
                </td>
                <td style="width: 100px">
                </td>
            </tr>
        </table>
    </asp:Panel>
  
    <asp:Panel ID="Panel3" runat="server" Height="50px" Visible="False" Width="100%">
        <table border="0" cellpadding="0" cellspacing="0" style="width: 100%">
            <caption>
                <br />
                故障登记<br />
            </caption>
            <tr>
                <td colspan="2">
                    你选择发生的地区为：<asp:Label ID="Label1" runat="server" Text="Label" Width="126px"></asp:Label></td>
            </tr>
            <tr>
                <td colspan="2" style="height: 19px">
                    请选择发生的设备名称：<asp:DropDownList ID="DropDownList2" runat="server">
                    </asp:DropDownList>
                    <asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="确定" /></td>
            </tr>
        </table>
    </asp:Panel>
    <asp:Panel ID="Panel4" runat="server" Height="50px" Visible="False" Width="100%">
        <table border="0" cellpadding="0" cellspacing="0" style="width: 100%">
            <caption>
                <br />
                故障登记<br />
            </caption>
            <tr>
                <td style="width: 100%">
                    你所选择的发生地区为：<asp:Label ID="Label2" runat="server" Text="Label"></asp:Label>。</td>
            </tr>
            <tr>
                <td style="width: 100%; height: 19px">
                    你所选择的发生设备为：<asp:Label ID="Label3" runat="server" Text="Label"></asp:Label>。</td>
            </tr>
            <tr>
                <td style="width: 100%; height: 24px">
                    请选择发生的网点名称：<asp:DropDownList ID="DropDownList3" runat="server">
                    </asp:DropDownList>
                    <asp:Button ID="Button3" runat="server" Text="确定" OnClick="Button3_Click" /></td>
            </tr>
        </table>
    </asp:Panel>
    <asp:Panel ID="Panel5" runat="server" Height="50px" Width="100%">
        <table border="0" cellpadding="0" cellspacing="0" style="width: 100%">
            <caption>
                <br />
                故障登记<br />
            </caption>
            <tr>
                <td style="width: 100％; height: 19px">
                    你所选择的发生地区为：<asp:Label ID="Label4" runat="server" Text="Label"></asp:Label></td>
            </tr>
            <tr>
                <td style="width: 100％">
                    你所选择的发生地区为：<asp:Label ID="Label5" runat="server" Text="Label"></asp:Label></td>
            </tr>
            <tr>
                <td style="width: 100％">
                    你所选择故障发生网点为：<asp:Label ID="Label6" runat="server" Text="Label"></asp:Label></td>
            </tr>
        </table>
        请选择维护人：<asp:DropDownList ID="DropDownList4" runat="server">
        </asp:DropDownList>
        <asp:Button ID="Button4" runat="server" Text="Button" /></asp:Panel>
</asp:Content>

Answer 2

key对应的value有重复的吧？DropDownList的value要求是唯一的。你可以通过hashtable来解决。

Answer 3

下次选择HTML code，居然还是C#，看起来

Answer 4

把load中的代码贴到
if(!ispostback)
{
  if (权限判断)
        {
            this.Panel1.Visible = true;
            this.Panel2.Visible = false;
            this.Panel3.Visible = false;
            this.Panel4.Visible = false;
            dpl1build();
        }
        else
        {
            this.Panel1.Visible = false;
            this.Panel2.Visible = true;
            this.Panel3.Visible = false;
            this.Panel4.Visible = false;
        }
       }

Answer 5

加上if(!ispostback) {..}
因为你没加这个判断,每次点击按钮时,都执行了一遍初始化方法,所以总是第一个值