DROPDOWNLIST重置为索引0负载 [英] DropdownList reset to to index 0 on load
问题描述
我将如何重置我的ASP：DropDownList的元素（其中有一个=服务器），以每一个在Firefox页面被重载时间指数0（F5为pressed）
How would I reset my asp:DropDownList element (which has a runat="server") to index 0 every time the page is "reloaded" in firefox (F5 is pressed).
如果你认为使用JavaScript ...请注意：我不使用形式和B：我不知道如何访问具有=服务器与JavaScript元素
If you suggest using javascript...please note that A: I am not using a form and B: I don't know how to access elements that have a runat="server" with javascript
如果这可以使用在.aspx页面上的脚本来完成....请解释的东西，你想一个ASP福利局不知道（即我，大声笑）
If this can be done using script on the .aspx page....please explain things you think an ASP newb would not know (ie. me, lol)
谢谢，
安德鲁：）
thanks, Andrew :)
推荐答案
把code中的的Page_Load事件做到这一点。
put code in the Page_Load event to do this
protected void Page_Load(object sender, EventArgs e)
{
myDropDownList.SelectedIndex =0;
}
编辑：
在回答您的意见，如果你把上面的逻辑里if语句来检查是否 Page.IsPostback = FALSE ，然后选定的索引将不会重新设置为0时刷新（它执行客户端回发）。作为一个例子来证明这一点，这里是设置在选择到自动回发一个下拉列表的页面
In response to your comments, If you have put the above logic inside of an if statement to check whether Page.IsPostback = false, then the selected index will not be set back to 0 upon refresh (which performs a client postback). As an example to demonstrate this, here is a page with a dropdown list set to autopostback upon selection
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!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>My Example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:DropDownList ID="ddl" runat="server" AutoPostBack="true" >
</asp:DropDownList>
</div>
</form>
</body>
</html>
下面是背后
public partial class _Default : System.Web.UI.Page
{
protected void Page_Init(object sender, EventArgs e)
{
//Apologies for Dairy Produce inspired list
ddl.Items.Add(new ListItem("Cheese"));
ddl.Items.Add(new ListItem("Yoghurt"));
ddl.Items.Add(new ListItem("Milk"));
ddl.Items.Add(new ListItem("Butter"));
}
protected void Page_Load(object sender, EventArgs e)
{
//Run the Page with this in first, then comment out
//the if statement to leave only ddl.SelectedIndex = 0;
if (!Page.IsPostBack)
{
ddl.SelectedIndex = 0;
}
}
}
由于将证明，当页面最初跑了，在刷新时，所选择的指数将在下拉列表中保留;当如果语句但是注释掉，在刷新时，选定的索引设置为0（在这种情况下的奶酪的）。
As will be demonstrated, when the page is originally ran, upon refresh, the selected index will be retained within the dropdown list; When the if statement is commented out however, upon refresh, the selected index is set to 0 (which in this case is Cheese).
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