Asp.net Dropdownlist选定的索引已更改且TextChanged事件未触发？（C＃）

Question

I am new to ASP>NET(C#). 我是ASP> NET（C＃）的新手。 But I am using Winform before. 但是我以前使用Winform。

In my Project I have two dropdown list. 在我的项目中，我有两个下拉列表。 if i change the one,.. the second will change auto. 如果我改变一个，..第二将改变自动。

But even event also not firing in ASP.net. 但是即使事件也没有在ASP.net中触发。 Without event how to i manage that?. 没有事件，我该如何管理？

<div id="Div1" class="ui-content ui-body-a" runat="server">
    <asp:dropdownlist id="ddlOutlet" runat="server" autopostback="True" onselectedindexchanged="ddlOutlet_SelectedIndexChanged"
        ontextchanged="ddlOutlet_TextChanged">
                </asp:dropdownlist>
    <br />
    <asp:dropdownlist id="ddlServedAt" runat="server">
                </asp:dropdownlist>
    <br />
    <asp:button id="btnLogin" runat="server" text="LogIn" />
</div>

C# C＃

I already Added items in both dropdown list in page load event. 我已经在页面加载事件的两个下拉列表中添加了项目。 But When I change the ddlOutlet selected index changed Event not firing. 但是当我更改ddlOutlet所选索引时，更改了事件未触发。 So I tried to TextChanged Events Also. 所以我也尝试了TextChanged事件。 But nothing happened. 但是什么也没发生。 What is problem?. 有什么问题吗？

Page Load Event - 页面加载事件-

protected void Page_Load(object sender, EventArgs e)
{
    HelpingFunctions hp = new HelpingFunctions();

    string id = Request.QueryString["id"];

    MySqlConnection connection = new MySqlConnection("server=192.168.1.100;username=mcubic;password=mcs@2011$;database=mcubic;");
    string query = "SELECT c.Outlet_Master_Name,d.Fbserved_Served FROM mcs_user a, mcs_user_outlet b,outlet_master c,fb_served d WHERE a.Mcs_User_Id='" + id + "' and"
                    + " a.Mcs_User_Id = b.Mcs_User_Outlet_User_Id and c.Outlet_Master_Id = b.Mcs_User_Outlet_Outlet_Id and c.Outlet_Master_Id=d.Fbserved_outletid";           
    MySqlCommand command = new MySqlCommand(query, connection);
    connection.Open();
    MySqlDataReader Reader = command.ExecuteReader();
    while (Reader.Read())
    {
        ddlOutlet.Items.Add(Reader[0].ToString());
        ddlServedAt.Items.Add(Reader[1].ToString());
    }
    connection.Close();


}

Selected Item - 选定项目-

protected void ddlOutlet_SelectedIndexChanged(object sender, EventArgs e)
{
    MySqlConnection connection = new MySqlConnection("server=192.168.1.100;username=mcubic;password=mcs@2011$;database=mcubic;");
    string query = "select Fbserved_Served from fb_served where Fbserved_outletid = (select Outlet_Master_Id from outlet_master where Outlet_Master_Name ='" + ddlOutlet.SelectedItem.ToString() + "')";
    MySqlCommand command = new MySqlCommand(query, connection);
    connection.Open();
    MySqlDataReader Reader = command.ExecuteReader();
    while (Reader.Read())
    {
        ddlServedAt.SelectedItem.Value = Reader[0].ToString();
    }
    connection.Close();
}

I read some same issue problem solutions, but they told to set AutoPostBack="True". 我阅读了一些相同问题的问题解决方案，但他们告诉他们设置AutoPostBack =“ True”。 I checked that also. 我也检查了。

I don't know why ASP.net hard to Event firing also?. 我不知道为什么ASP.net很难触发事件？

UPDATED QUESTION 更新的问题

In my Project,.. I am using jquerymobile(http://jquerymobile.com/) with ASP.Net and mysql. 在我的项目中，..我正在将jquerymobile（http://jquerymobile.com/）与ASP.Net和mysql一起使用。 I have two drop down list controls and ONE button. 我有两个下拉列表控件和一个按钮。

But When I change the ddlOutlet selected index changed Event not firing. 但是当我更改ddlOutlet所选索引时，更改了事件未触发。 After the button Click the Events Are fired Correctly. 在按钮之后，单击“正确触发事件”。 But Before that They not fire. 但在此之前，他们不会开火。 I do't know Why its happen. 我不知道为什么会这样。

I Give my Complete Code Below. 我在下面提供完整的代码。

My Complete ASPX File :- 我完整的ASPX文件：-

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="OutLet.aspx.cs" Inherits="MobileApp.OutLet" %>

<!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">
    <title></title>
     <meta name="viewport" content="width=device-width; height=device-height; initial-scale=1.0; maximum-scale=1.5; user-scalable=no;" />
     <link href="Styles/jquery.mobile-1.0b3.css" rel="stylesheet" type="text/css" />

    <script src="Scripts/jquery-ui-1.8.16.custom.min.js" type="text/javascript"></script>
    <script src="Scripts/jquery-1.6.2.min.js" type="text/javascript"></script>
    <script src="Scripts/jquery.mobile-1.0b3.js" type="text/javascript"></script>
</head>
<body>
    <form id="form1" runat="server" data-ajax="false">
        <div id="mainheader" class="ui-header-fixed ui-bar-a">  

        </div>
        <div id="Div1" class="ui-content ui-body-a" runat="server">

           <%-- <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                <ContentTemplate>--%>
                    <asp:DropDownList ID="ddlOutlet" runat="server" 
    AutoPostBack="True" onselectedindexchanged="ddlOutlet_SelectedIndexChanged" 
    ontextchanged="ddlOutlet_TextChanged">
                    </asp:DropDownList>
                    <br />
                    <asp:DropDownList ID="ddlServedAt" runat="server" AutoPostBack="True">
                    </asp:DropDownList>
                    <br />
                    <asp:Button ID="btnLogin" runat="server" Text="LogIn" 
                onclick="btnLogin_Click" />
               <%-- </ContentTemplate>
            </asp:UpdatePanel>   --%>       
        </div>
    </form>
</body>
</html>

my Code - 我的代码-

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using MySql.Data.MySqlClient;

namespace MobileApp
{
    public partial class OutLet : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            HelpingFunctions hp = new HelpingFunctions();

            string id = Request.QueryString["id"];
            if (!Page.IsPostBack)
            {
                MySqlConnection connection = new MySqlConnection("server=192.168.1.100;username=mcubic;password=mcs@2011$;database=mcubic;");
                string query = "SELECT c.Outlet_Master_Name,d.Fbserved_Served FROM mcs_user a, mcs_user_outlet b,outlet_master c,fb_served d WHERE a.Mcs_User_Id='" + id + "' and"
                                + " a.Mcs_User_Id = b.Mcs_User_Outlet_User_Id and c.Outlet_Master_Id = b.Mcs_User_Outlet_Outlet_Id and c.Outlet_Master_Id=d.Fbserved_outletid";
                MySqlCommand command = new MySqlCommand(query, connection);
                connection.Open();
                MySqlDataReader Reader = command.ExecuteReader();
                while (Reader.Read())
                {
                    ddlOutlet.Items.Add(Reader[0].ToString());
                    ddlServedAt.Items.Add(Reader[1].ToString());
                }
                connection.Close();
            }

        }

        protected void ddlOutlet_SelectedIndexChanged(object sender, EventArgs e)
        {
            MySqlConnection connection = new MySqlConnection("server=192.168.1.100;username=mcubic;password=mcs@2011$;database=mcubic;");
            string query = "select Fbserved_Served from fb_served where Fbserved_outletid = (select Outlet_Master_Id from outlet_master where Outlet_Master_Name ='" + ddlOutlet.SelectedItem.ToString() + "')";
            MySqlCommand command = new MySqlCommand(query, connection);
            connection.Open();
            MySqlDataReader Reader = command.ExecuteReader();
            while (Reader.Read())
            {
                ddlServedAt.SelectedValue = Reader[0].ToString();
            }
            connection.Close();
        }

        protected void ddlOutlet_TextChanged(object sender, EventArgs e)
        {
            //MySqlConnection connection = new MySqlConnection("server=192.168.1.100;username=mcubic;password=mcs@2011$;database=mcubic;");
            //string query = "select Fbserved_Served from fb_served where Fbserved_outletid = (select Outlet_Master_Id from outlet_master where Outlet_Master_Name ='" + ddlOutlet.SelectedItem.ToString() + "')";
            //MySqlCommand command = new MySqlCommand(query, connection);
            //connection.Open();
            //MySqlDataReader Reader = command.ExecuteReader();
            //while (Reader.Read())
            //{
            //    ddlServedAt.SelectedItem.Value = Reader[0].ToString();
            //}
            //connection.Close();
        }

        protected void btnLogin_Click(object sender, EventArgs e)
        {

        }
    }
}

Answer 1

Create the drop down list(the one that changes the content of the other one) 创建下拉列表（一个更改另一个列表的内容）

Activity: <asp:DropDownList ID="cmbActivity" runat="server" OnSelectedIndexChanged="cmbActivity_SelectedIndexChanged" AutoPostBack="true" />

Then in your C#, your load event should be like this 然后在您的C＃中，您的load事件应如下所示

if (Session["staffId"] == null)
        {
            Response.Redirect("~/login.aspx");
        }
        else
        {
            if (!IsPostBack)
            {
             cmbActivity.DataSource = a;
             cmbActivity.DataTextField = "activityName";
             cmbActivity.DataValueField = "activiyId";
            }
        }

Your selectedIndex_Changed method still remains the same. 您的selectedIndex_Changed方法仍然保持不变。 This should work. 这应该工作。 Have more than one item in the list to be sure. 确保列表中有多个项目。 I hope this helps 我希望这有帮助

Answer 2

try by Adding Page.IsPostBack in your page_Load event... 尝试通过在page_Load事件中添加Page.IsPostBack ...

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        //your page load code.....
    }
}

EDIT - 1 编辑-1

Sample Code of ASPX page in Web Application Web应用程序中ASPX页面的示例代码

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %>

<!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">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
     <asp:DropDownList  id="id1" runat="server" AutoPostBack="true" 
            onselectedindexchanged="id1_SelectedIndexChanged">
        <asp:ListItem Text="1" Value="1"></asp:ListItem>
        <asp:ListItem Text="2" Value="2"></asp:ListItem>
        </asp:DropDownList>
        <asp:DropDownList  id="id2" runat="server"></asp:DropDownList>
    </div>
    </form>
</body>
</html>

Sample code of code behind in Web Application Web应用程序中的代码示例代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication1
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }
        protected void id1_SelectedIndexChanged(object sender, EventArgs e)
        {

        }
    }
}

Sample code of ASPX page in Website 网站中ASPX页面的示例代码

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default4.aspx.cs" Inherits="Default4" %>

<!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">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:DropDownList  id="id1" runat="server" AutoPostBack="true" 
            onselectedindexchanged="id1_SelectedIndexChanged">
        <asp:ListItem Text="1" Value="1"></asp:ListItem>
        <asp:ListItem Text="2" Value="2"></asp:ListItem>
        </asp:DropDownList>
        <asp:DropDownList  id="id2" runat="server"></asp:DropDownList>
    </div>
    </form>
</body>
</html>

Sample code of Code behind in Website 网站中后面的代码示例代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Default4 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void id1_SelectedIndexChanged(object sender, EventArgs e)
    {

    }
}

Answer 3

OP在他的问题中已经有这个问题，但是我缺少了autopostback="True"

Asp.net Dropdownlist选定的索引已更改且TextChanged事件未触发？（C＃）

问题描述

3 个解决方案

解决方案1
3 2013-04-04 21:50:59

解决方案2
2 已采纳 2012-02-15 08:56:20

解决方案3
0 2018-07-10 14:07:58

Asp.net Dropdownlist选定的索引已更改且TextChanged事件未触发？ （C＃）

问题描述

3 个解决方案

解决方案1 3 2013-04-04 21:50:59

解决方案2 2 已采纳 2012-02-15 08:56:20

解决方案3 0 2018-07-10 14:07:58

Asp.net Dropdownlist选定的索引已更改且TextChanged事件未触发？（C＃）

解决方案1
3 2013-04-04 21:50:59

解决方案2
2 已采纳 2012-02-15 08:56:20

解决方案3
0 2018-07-10 14:07:58