在dropdownlist中选择值，然后在asp.net中的另一个dropdownlist中显示velue [英] selected value in dropdownlist and then show velue in another dropdownlist in asp.net

问题描述

在下拉列表中选择值，然后在asp.net中的另一个下拉列表中显示velue. 要填充数据库，请调用数据库以填充下拉列表.

后面的代码

protected void Page_Load(object sender, EventArgs e)
{
    DropDownList1.Items.Add(new ListItem("Sandip", "1"));
    DropDownList1.Items.Add(new ListItem("Jon", "2"));
    DropDownList1.Items.Add(new ListItem("Michael", "3"));
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    DropDownList2.Items.Clear();
    if (DropDownList1.SelectedIndex == 0)
    {
        DropDownList2.Items.Add(new ListItem("DOT.NET", "1"));
        DropDownList2.Items.Add(new ListItem("C#", "2"));
        DropDownList2.Items.Add(new ListItem("ASP.NET", "3"));
        DropDownList2.Items.Add(new ListItem("LINQ", "4"));
    }
    else if (DropDownList1.SelectedIndex == 1)
    {
        DropDownList2.Items.Add(new ListItem("DOT.NET", "1"));
        DropDownList2.Items.Add(new ListItem("VB.NET", "2"));
        DropDownList2.Items.Add(new ListItem("ASP.NET", "3"));
    }
    else if (DropDownList1.SelectedIndex == 2)
    {
        DropDownList2.Items.Add(new ListItem("PHP", "1"));
        DropDownList2.Items.Add(new ListItem("MYSQL", "2"));
    }

}

aspx代码

<asp:dropdownlist id="DropDownList1" runat="server" autopostback="True" xmlns:asp="#unknown">
    onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:dropdownlist>
<br />
<br />
<asp:dropdownlist id="DropDownList2" runat="server" xmlns:asp="#unknown">
</asp:dropdownlist>

欢呼声

这称为级联dropdownlist.这是一篇介绍两种方法的文章.也包含示例项目.参照它，看看是否有帮助

面向初学者的AJAX(第2部分)-使用XMLHttpRequest和jQuery AJAX实施级联下拉列表 [ ^ ]

这应该为您提供一些您需要的信息
解决方案

Here is the code for you.
To fill up the database, call the database to populate dropdown.

code behind

protected void Page_Load(object sender, EventArgs e)
{
    DropDownList1.Items.Add(new ListItem("Sandip", "1"));
    DropDownList1.Items.Add(new ListItem("Jon", "2"));
    DropDownList1.Items.Add(new ListItem("Michael", "3"));
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    DropDownList2.Items.Clear();
    if (DropDownList1.SelectedIndex == 0)
    {
        DropDownList2.Items.Add(new ListItem("DOT.NET", "1"));
        DropDownList2.Items.Add(new ListItem("C#", "2"));
        DropDownList2.Items.Add(new ListItem("ASP.NET", "3"));
        DropDownList2.Items.Add(new ListItem("LINQ", "4"));
    }
    else if (DropDownList1.SelectedIndex == 1)
    {
        DropDownList2.Items.Add(new ListItem("DOT.NET", "1"));
        DropDownList2.Items.Add(new ListItem("VB.NET", "2"));
        DropDownList2.Items.Add(new ListItem("ASP.NET", "3"));
    }
    else if (DropDownList1.SelectedIndex == 2)
    {
        DropDownList2.Items.Add(new ListItem("PHP", "1"));
        DropDownList2.Items.Add(new ListItem("MYSQL", "2"));
    }

}

aspx code

<asp:dropdownlist id="DropDownList1" runat="server" autopostback="True" xmlns:asp="#unknown">
    onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:dropdownlist>
<br />
<br />
<asp:dropdownlist id="DropDownList2" runat="server" xmlns:asp="#unknown">
</asp:dropdownlist>

cheers

This is called cascading dropdownlist. here is an article that presents 2 approaches to do the same. contains sample projects too. refer it and see if it could be helpful

AJAX for beginners (Part 2) - Using XMLHttpRequest and jQuery AJAX to implement a cascading dropdown[^]

This should give you some information you need
cascading dropdownlist [^]

这篇关于在dropdownlist中选择值，然后在asp.net中的另一个dropdownlist中显示velue的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！