在 javascript 中访问 ASP HiddenField
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Accessing ASP HiddenField in javascript
提问by Jordan
I have been searching through here and google for a few days now, trying to figure out why I cannot get the value of a hiddenfield variable in javascript. When accessed, the value is returned as undefined.
I have an ASP HiddenField inside an UpdatePanel which is part of a custom user control in a .aspx web page (standard issue).
我已经在这里和谷歌搜索了几天，试图找出为什么我无法在 javascript 中获取 hiddenfield 变量的值。访问时，该值返回为未定义。
我在 UpdatePanel 中有一个 ASP HiddenField，它是 .aspx 网页中自定义用户控件的一部分（标准问题）。
In my user control, I need to get the .Value of the HiddenField (hdnServer) in javascript after setting it in C#. But for some reason the following is not getting the correct value.
在我的用户控件中，我需要在 C# 中设置后在 javascript 中获取 HiddenField (hdnServer) 的 .Value。但由于某种原因，以下没有得到正确的值。
The MessageBox in the C# code returns the correct value (the code here has test values), but when accessed in javascript is undefined.
C# 代码中的 MessageBox 返回正确的值（这里的代码有测试值），但在 javascript 中访问时未定义。
userControl.ascx:
userControl.ascx：
//this function is called when the timer created in document.ready() elapses
//returns the correct hdnServer value in the check.
var checkHdn = function () {
var temp = document.getElementById("<%=hdnServer.ClientID%>").value;
temp = temp.toString();
if (temp != "") {
$('#LoadingViewer').hide();
clearInterval(checkSrv);
//enable start button
$('#startBtn').attr("Enabled", "true");
}
};
function RdpConnect() {
//serverName = undefined here. should be ip address when set in c#
var serverName = document.getElementById("<%= hdnServer.ClientID %>").value;
alert(serverName);
if (serverName != "") {
MsRdpClient.Server = serverName;
}
};
userControl.ascx.cs code-behind:
userControl.ascx.cs 代码隐藏：
public partial class userControl : System.Web.UI.UserControl
{
System.Timers.Timer timer;
protected void Page_Load(object sender, EventArgs e)
{
timer = new System.Timers.Timer(5000);
timer.Start();
}
protected void testOnTick(object sender, System.Timers.ElapsedEventArgs e)
{
hdnServer.Value = "test value";
startBtn.Enabled = true;
timer.Enabled = false;
}
}
Here is the asp for HiddenField just in case: userControl.ascx:
这是 HiddenField 的 asp 以防万一：userControl.ascx：
<asp:ScriptManager ID="ScriptManager1" runat="server" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Always">
<Triggers>
<!--trigger not used -->
<!-- <asp:AsyncPostBackTrigger ControlID="Timer1" EventName="Tick" />-->
</Triggers>
<ContentTemplate>
<asp:HiddenField ID="hdnServer" runat="server" />
<asp:Label ID="Label1" Text="Loading, please wait." CssClass="loading" runat="server"
Font-Size="XX-Large" />
</ContentTemplate>
</asp:UpdatePanel>
Thank you for any advice in advance!
提前感谢您的任何建议！
EDIT: messagebox removed.. Here is rendered html: http://pastie.org/3122247
编辑：消息框已删除..这是呈现的 html：http: //pastie.org/3122247
回答by scottm
You need to set ClientIDMode if you want to make it simple:
如果你想让它变得简单，你需要设置 ClientIDMode：
<asp:HiddenField runat="server" ClientIDMode="Static" Id="hidServer"/>
<script type="text/javascript">
alert($("#hidServer").val());
</script>
Or, use the ClientID property if you don't set ClientIDMode:
或者，如果您未设置 ClientIDMode，请使用 ClientID 属性：
<asp:HiddenField runat="server" Id="hidServer"/>
<script type="text/javascript">
alert($("<%= hidServer.ClientID %>").val());
</script>
回答by justinlabenne
User controls have always been a strange issue for referencing using js and then master pages to go along with it.
用户控件对于使用 js 和母版页进行引用一直是一个奇怪的问题。
For the hidden field do this:
对于隐藏字段，请执行以下操作：
<asp:HiddenField ID="hdnServer" runat="server" ClientIDMode="Static" />
in the js, do this:
在 js 中，执行以下操作：
var serverName = document.getElementById('hdnServer').value;
回答by Bin Taleb
you need to use 'not "like:
你需要使用'不"喜欢：
var serverName = document.getElementById('<%= hdnServer.ClientID %>').value;
be careful don't use ". You have only use '
小心不要使用". 你只有使用'
回答by Steve Wellens
Try this:
试试这个：
var temp = $('#mytestcontrol_hdnServer').val();
回答by Robert Wilson
You can do this:
你可以这样做：
var temp = $('#hdnServer').val();
Instead of :
代替 ：
var temp = document.getElementById("<%=hdnServer.ClientID%>").value;
Also change this:
也改变这个：
var serverName = document.getElementById("<%= hdnServer.ClientID %>").value;
To this:
对此：
var serverName = $('#hdnServer').val();
