HiddenField Cannot be Referenced in CodeBehind file

Question

I have the following HiddenField in my ASP.NET 2.0 webform:

<asp:HiddenField ID="HiddenModel" runat="server" 
OnValueChanged="HiddenModel_ValueChanged" />

My codebehind references HiddenModel in this if..else statement:

if (serial.Text.ToString() != "0")
{
CarpetMultiView.ActiveViewIndex = 1;
HiddenModel.Value = model.SelectedItem.Text.ToString();
LabelCurrent.Text = "Your Current Selection is :
Make-" + make.SelectedItem.Text.ToString() + " Model-" + 
model.SelectedItem.Text.ToString() + " S/N-" + serial.SelectedItem.Text.ToString();
Page.Title = make.SelectedItem.ToString() + " " + model.SelectedItem.ToString() + " " + 
serial.SelectedItem.ToString() + " " + "Carpet";
}

When I debug the solution using VWD 2005, I receive the following error:

The name 'HiddenModel' does not exist in the current context

My @Page directive inherits carpet_template which matches the codebehind class:

public partial class carpet_template : System.Web.UI.Page

How can I resolve these and other similar errors?

What happens if you manually declare the HiddenField in codebehind? `Protected WithEvents HiddenModel As System.Web.UI.WebControls.HiddenField` Have a look here for more tips: http://stackoverflow.com/a/1981228/284240 — Tim Schmelter, Dec 29 '11 at 22:35
@Oded: The code block is in Page_Load and make_SelectedIndexChanged methods. — SidC, Dec 29 '11 at 22:46

score 1 · Accepted Answer · answered Dec 29 '11 at 23:11

From the link below: "If you are testing in IIS, you should go to the website menu in VWD, click start options, click "build" on the tree in the left pane, and on the dropdown list labelled "Before running startup page" select "No Build".

Full story HERE.

score 0 · Answer 2 · answered Aug 12 '14 at 05:32

Delete all the backup copies of the same files. I had a backup copy of the same file in same folder, after deleting those backup files - solution is compiling without any errors.

Got this solution from link below: [slash84]
http://forums.asp.net/post/3060379.aspx

score 0 · Answer 3 · answered Dec 29 '11 at 22:39

Its difficult to be sure when the code is out of context of the page life cycle, but it sounds like asp.net simply doesn't accept that the field currently exists.

The most logical reason is that the hidden field doesn't yet exist in the page life cycle (see page lifecycle) - is the code run before the page has been loaded or before the control has been rendered?

Alternatively if there is a problem with the form you could get this behaviour (eg if the hidden field is not within the form tags).

HiddenField Cannot be Referenced in CodeBehind file

3 Answers3