Asp.net Dropdownlist选择的索引已更改且TextChanged事件未启动?(C#)

本文关键字：事件 TextChanged 启动 选择 Dropdownlist net 索引 Asp | 更新日期: 2023-09-27 18:24:32

我是ASP>NET（C#）的新手。但我以前使用过Winform。

在我的项目中，我有两个下拉列表。如果我换一个，。。第二个将变为auto。

但即使是事件也不会在ASP.net中启动。如果没有事件，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#

我已经在页面加载事件的两个下拉列表中添加了项目。但是当我更改ddlOutlet所选的索引时，Event未启动。所以我也尝试用TextChanged事件。但什么也没发生。问题出在哪里？。

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();

}

所选项目-

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();
}

我读过一些相同问题的解决方案，但他们告诉我要将AutoPostBack设置为"True"。我也查过了。

我不知道为什么ASP.net也很难事件触发？。

更新的问题

在我的项目中，。。我正在使用jquerymobile(http://jquerymobile.com/)Net和mysql。我有两个下拉列表控件和一个按钮。

但是当我更改ddlOutlet所选的索引时，Event未启动。点击按钮后，事件被正确触发。但在此之前，他们不会开火。我不知道为什么会这样。

我在下面给出我的完整代码。

我的完整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>

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)
        {
        }
    }
}

Asp.net Dropdownlist选择的索引已更改且TextChanged事件未启动?(C#)

创建下拉列表（更改另一个内容的列表）

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

然后在你的C#中，你的加载事件应该是这样的

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

您选择的Index_Changed方法仍然保持不变。这应该行得通。要确定列表中有多个项目。我希望这能帮助

尝试在page_Load事件中添加Page.IsPostBack。。。

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

编辑-1

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>

Web应用程序中代码隐藏的示例代码

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)
        {
        }
    }
}

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>

网站中代码隐藏的示例代码

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)
    {
    }
}

OP在他的问题中已经有了这个问题，但我缺少autopostback="True"

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