本文介绍了为什么当我选择其他时drop downlist4的值没有改变.的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
为什么当我选择其他选项时drop downlist4的值没有变化.它仅从满足第一个条件的表中获取第一条记录.下拉列表与dropdownlist 3链接.
我的HTML部分和CS部分在下面给出.
HTML部分
Why the value of drop downlist4 is not changing when i select other.It is getting only first record from table which satisfied first condition.The drop down list is linked with dropdownlist 3.
My HTML part and CS part is given below .
HTML part
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Selection4go.aspx.cs" Inherits="selection4go" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
</head>
<body>
<form id="form1" runat="server">
<div align="center">
<table class="style1">
<tr>
<td>
</td>
</tr>
<tr>
<td>
<table class="style2">
<tr>
<td>
</td>
<td>
</td>
<td>
<asp:PlaceHolder ID="ph1" runat="server"></asp:PlaceHolder>
</td>
<td>
</td>
</tr>
<tr>
<td>
</td>
<td>
Class</td>
<td>
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"
DataSourceID="SqlDataSource1" DataTextField="class_name"
DataValueField="class_name">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:ApplicationServices %>"
SelectCommand="SELECT * FROM [class]"></asp:SqlDataSource>
</td>
<td>
</td>
</tr>
<tr>
<td>
</td>
<td>
Board</td>
<td>
<asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="True"
DataSourceID="SqlDataSource2" DataTextField="board" DataValueField="board">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource2" runat="server"
ConnectionString="<%$ ConnectionStrings:ApplicationServices %>"
SelectCommand="SELECT * FROM [board]"></asp:SqlDataSource>
</td>
<td>
</td>
</tr>
<tr>
<td>
</td>
<td>
City</td>
<td>
<asp:DropDownList ID="DropDownList3" runat="server" AutoPostBack="True"
DataSourceID="SqlDataSource3" DataTextField="cityname"
DataValueField="stateid">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource3" runat="server"
ConnectionString="<%$ ConnectionStrings:ApplicationServices %>"
SelectCommand="SELECT * FROM [city]"></asp:SqlDataSource>
</td>
<td>
</td>
</tr>
<tr>
<td>
</td>
<td>
State</td>
<td>
<asp:DropDownList ID="DropDownList4" runat="server"
DataSourceID="SqlDataSource4" DataTextField="statename"
DataValueField="stateid" AutoPostBack="True">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource4" runat="server"
ConnectionString="<%$ ConnectionStrings:ApplicationServices %>"
SelectCommand="SELECT * FROM [state] WHERE ([stateid] = @stateid)">
<SelectParameters>
<asp:ControlParameter ControlID="DropDownList3" DefaultValue="-99"
Name="stateid" PropertyName="SelectedValue" Type="String" />
</SelectParameters>
</asp:SqlDataSource>
</td>
<td>
</td>
</tr>
<tr>
<td>
</td>
<td>
</td>
<td>
<asp:Button ID="Button1" runat="server" onclick="Button1_Click"
Text="PROCEED==>" Width="215px" />
</td>
<td>
</td>
</tr>
</table>
</td>
</tr>
<tr>
<td>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
CS零件
CS Part
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
public partial class selection4go : System.Web.UI.Page
{
SqlConnection con;
SqlCommand cmd;
SqlDataAdapter da;
DataSet ds;
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
if (Request.QueryString["t1"].ToString() != null)
{
string mail = Request.QueryString["t1"].ToString();
SqlConnection con = new SqlConnection(System.Web.Configuration.WebConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString);
con.Open();
ds = new DataSet();
string sql = "select email,rclass,board,city,state from registration where email='" + mail +"'";
da = new SqlDataAdapter(sql, con);
da.Fill(ds, "registration");
DataRow dRow = ds.Tables["registration"].Rows[0];
string em = dRow.ItemArray.GetValue(0).ToString();
string s = dRow.ItemArray.GetValue(1).ToString();
string t = dRow.ItemArray.GetValue(2).ToString();
string u = dRow.ItemArray.GetValue(3).ToString();
string v = dRow.ItemArray.GetValue(4).ToString();
int r = 0;
DataRow[] rs;
rs = ds.Tables["registration"].Select("email='" + mail + "'");
r = rs.Length;
if (r > 0)
{
DataRow dr;
dr = rs[0];
string m = dr["rclass"].ToString();
string n = dr["board"].ToString();
string o = dr["city"].ToString();
string p = dr["state"].ToString();
string a, b, c, d;
a = DropDownList1.SelectedItem.Text.Trim();
b = DropDownList2.SelectedItem.Text.Trim();
c = DropDownList3.SelectedItem.Text.Trim();
d = DropDownList4.SelectedItem.Text.Trim();
if (m != a)
{
System.Web.UI.WebControls.Label lbl1 = new System.Web.UI.WebControls.Label();
lbl1.ForeColor = System.Drawing.Color.Yellow;
lbl1.BackColor = System.Drawing.Color.Blue;
lbl1.Text = "This ID is not Valid for Class " + a ;
ph1.Controls.Add(lbl1);
}
else if (n != b)
{
System.Web.UI.WebControls.Label lbl1 = new System.Web.UI.WebControls.Label();
lbl1.ForeColor = System.Drawing.Color.Yellow;
lbl1.BackColor = System.Drawing.Color.Blue;
lbl1.Text = "This ID is not Valid for Board " + b;
ph1.Controls.Add(lbl1);
}
else if (o != c)
{
System.Web.UI.WebControls.Label lbl1 = new System.Web.UI.WebControls.Label();
lbl1.ForeColor = System.Drawing.Color.Yellow;
lbl1.BackColor = System.Drawing.Color.Blue;
lbl1.Text = "This ID is not Valid for City " + c;
ph1.Controls.Add(lbl1);
}
else if (p != d)
{
System.Web.UI.WebControls.Label lbl1 = new System.Web.UI.WebControls.Label();
lbl1.ForeColor = System.Drawing.Color.Yellow;
lbl1.BackColor = System.Drawing.Color.Blue;
lbl1.Text = "This ID is not Valid for Board " + d;
ph1.Controls.Add(lbl1);
}
else
{
Response.Redirect("ANScontrol.aspx");
}
}
else
{
System.Web.UI.WebControls.Label lbl1 = new System.Web.UI.WebControls.Label();
lbl1.ForeColor = System.Drawing.Color.Yellow;
lbl1.BackColor = System.Drawing.Color.Blue;
lbl1.Text = "Pleasse select Valid Selection as per ur registration";
ph1.Controls.Add(lbl1);
}
}
}
}推荐答案
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