Accessing value of a hidden field on Masterpage from codebehind

In a follow up to my previous question, I want to get the value of the hidden input field from the child page codebehind.

I tried HtmlInputHidden hdnID = (HtmlInputHidden)Page.Master.FindControl("ctl00_hdnField"); but I get a “null” value.

enter image description here

A snippet of the Masterpage is:

<head runat="server">
    <title>
        <asp:ContentPlaceHolder ID="TitleContent" runat="server"></asp:ContentPlaceHolder>
        <asp:Literal ID="Literal2" runat="server" Text=" : Logistics Management" />
    </title>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

    <link href="~/css/styles.css" rel="nofollow noreferrer noopener" rel="stylesheet" type="text/css" />

    <asp:ContentPlaceHolder ID="ScriptCssContent" runat="server">
    </asp:ContentPlaceHolder>

</head>
<body>

<form id="form1" runat="server">
    ......
    ......
    ......
        <div id="container">
        ....
        ....
        ....
                <div id="content" style="z-index:0;">
                <asp:HiddenField ID="hdnField" runat="server" Value=""/>
                ....
                ....
                ....
                        <asp:ContentPlaceHolder ID="MainContent" runat="server">

                        </asp:ContentPlaceHolder>
            </div>
        </div>
</form>

On my Child aspx page, I have this javascript block:

window.onload = function() {
    var newDate = new Date();
    var hidField = document.getElementById("ctl00_hdnField");

    if (hidField != null)
        hidField.value = newDate.toLocaleString();
}

When I “Add Watch” to

document.getElementById(“ctl00_hdnField”)

the value is correct.

Question: How would I access the value inside hdnField control, from codebehind?

Contents hide

Answers:

Method 1

Method 2

Method 3

Method 4

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

So change it FROM

HtmlInputHidden hdnID = (HtmlInputHidden)Page.Master.FindControl("ctl00_hdnField");

HiddenField hdnID = (HiddenField)Page.Master.FindControl("hdnField");

It’s just a casting thing – notice HtmlInputHidden changed to HiddenField. You also don’t need the ct100_ part – this is just so the HTML rendered element has a unique ID.

The control on your page is an asp.net control, not a generic HTML control.

You would use HtmlInputHidden if you put a generic <input type="hidden" /> in your HTML.

Method 2

You should create a property in Masterpage which wrap the HiddenField.

public String HdnFieldValue
{
get
{
    return hidField.Value;
}
set
{
    hidField.Value = value;
}
}

And in page code behind you can access it like this:

((YourCustomMaster)Page.Master).HdnFieldValue

If something is not clear please ask me.

Method 3

I don’t think you need to prefix the hidden field’s ID with ctl00_, just use the normal ID:

(HtmlInputHidden)Page.Master.FindControl("hdnField");

Method 4

Use something like:

if (Page.Master.FindControl("hdnField") != null)
{
    String myValue = (HtmlInputHidden)Page.Master.FindControl("hdnField").value;
}

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

0 0 votes

Article Rating