首页 / 脚本样式 / JavaScript / Jquery实现无刷新DropDownList联动实现代码

先看HTML,我们引用Jquery,放两个DropDownList:
复制代码 代码如下:
<style type="text/css">
#ddlEmployeeCars
{
display:none;
position:absolute;
top:50px;
left:9px;
}
</style>
<script language="javascript" type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>

<asp:DropDownList ID="ddlEmployee" runat="server" AppendDataBoundItems="true">
<asp:ListItem Text="（Please Select）" Value="0" Selected="True" />
</asp:DropDownList>
<asp:DropDownList ID="ddlEmployeeCars" runat="server">
</asp:DropDownList>

接着写核心的Script:
复制代码 代码如下:
<script language="javascript" type="text/javascript">
$（function（） {
var $ddl = $（"select[name$=ddlEmployee]"）;
var $ddlCars = $（"select[name$=ddlEmployeeCars]"）;
$ddl.focus（）;
$ddl.bind（"change keyup", function（） {
if （$（this）.val（） ！= "0"） {
loadEmployeeCars（$（"select option:selected"）.val（））;
$ddlCars.fadeIn（"slow"）;
} else {
$ddlCars.fadeOut（"slow"）;
}
}）;
}）;

function loadEmployeeCars（selectedItem） {
$.ajax（{
type: "POST",
url: "Default.aspx/FetchEmployeeCars",
data: "{id: " + selectedItem + "}",
contentType: "application/json; charset=utf-8",
dataType: "json",
async: true,
success: function Success（data） {
printEmployeeCars（data.d）;
}
}）;
}

function printEmployeeCars（data） {
$（"select[name$=ddlEmployeeCars] > option"）.remove（）;
for （var i = 0; i < data.length; i++） {
$（"select[name$=ddlEmployeeCars]"）.append（
$（"<option></option>"）.val（data[i].Id）.html（data[i].Car）
）;
}
}
</script>

非常简单，检查值是不是０，然后ajax传值到server，成功后remove掉原来的option,append新的option.
看下WebPage的code:
复制代码 代码如下:
public partial class _Default : System.Web.UI.Page
{
[WebMethod]
public static List<EmployeeCar> FetchEmployeeCars（int id）
{
var emp = new EmployeeCar（）;
return emp.FetchEmployeeCars（id）;
}

protected void Page_Load（object sender, EventArgs e）
{
if （！IsPostBack）
{
var employees = new Employee（）;
ddlEmployee.DataSource = employees.FetchEmployees（）;
ddlEmployee.DataTextField = "Surname";
ddlEmployee.DataValueField = "Id";
ddlEmployee.DataBind（）;
}
}
}

我们的Datasource class:
复制代码 代码如下:
public class EmployeeCar
{
public int Id { get; set; }
public string Car { get; set; }

private static List<EmployeeCar> LoadData（）
{
return new List<EmployeeCar>
{
new EmployeeCar {Id = 1, Car = "Ford"},
new EmployeeCar {Id = 1, Car = "Holden"},
new EmployeeCar {Id = 1, Car = "Honda"},
new EmployeeCar {Id = 2, Car = "Toyota"},
new EmployeeCar {Id = 2, Car = "General Motors"},
new EmployeeCar {Id = 2, Car = "Volvo"},
new EmployeeCar {Id = 3, Car = "Ferrari"},
new EmployeeCar {Id = 3, Car = "Porsche"},
new EmployeeCar {Id = 3, Car = "Ford2"}
};
}

public List<EmployeeCar> FetchEmployeeCars（int id）
{
return （from p in LoadData（）
where p.Id == id
select p）.ToList（）;
}
}

public class Employee
{
public int Id { get; set; }
public string GivenName { get; set; }
public string Surname { get; set; }

public List<Employee> FetchEmployees（）
{
return new List<Employee>
{
new Employee {Id = 1, GivenName = "Tom", Surname = "Hanks"},
new Employee {Id = 2, GivenName = "Hugh", Surname = "Jackman"},
new Employee {Id = 3, GivenName = "Petter", Surname = "Liu"}
};
}

public Employee FetchEmployee（int id）
{
var employees = FetchEmployees（）;
return （from p in employees
where p.Id == id
select p）.First（）;
}
}

完了。希望这篇POST对您有帮助。