BC30560: 'default_aspx' is ambiguous in the namespace 'ASP' - asp.net

Question

When I compiled my latest asp.net program and trying to run on the test server, I am getting this error
Line 46: Dim dependencies() As String
Line 47: CType(Me,Global.System.Web.UI.Page).AppRelativeVirtualPath = "~/default.aspx"
Line 48: If (Global.ASP.default_aspx.__initialized = false) Then
Line 49: dependencies = New String(0) {}
Line 50: dependencies(0) = "~/default.aspx"
Source File: C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\ocbuild\c0c442ff\f0292c99\App_Web_default.aspx.cdcab7d2.4ubu1wgu.0.vb Line: 48
Detailed errors when I expand the compiler output...
Microsoft (R) Visual Basic Compiler version 8.0.50727.3053
for Microsoft (R) .NET Framework version 2.0.50727.3053
Copyright (c) Microsoft Corporation. All rights reserved.
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\ocbuild\c0c442ff\f0292c99\App_Web_default.aspx.cdcab7d2.4ubu1wgu.0.vb(48) : error BC30560: 'default_aspx' is ambiguous in the namespace 'ASP'.
If (Global.ASP.default_aspx.__initialized = false) Then
~~~~~~~~~~~~~~~~~~~~~~~
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\ocbuild\c0c442ff\f0292c99\App_Web_default.aspx.cdcab7d2.4ubu1wgu.0.vb(51) : error BC30560: 'default_aspx' is ambiguous in the namespace 'ASP'.
Global.ASP.default_aspx.__fileDependencies = Me.GetWrappedFileDependencies(dependencies)
~~~~~~~~~~~~~~~~~~~~~~~
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\ocbuild\c0c442ff\f0292c99\App_Web_default.aspx.cdcab7d2.4ubu1wgu.0.vb(52) : error BC30560: 'default_aspx' is ambiguous in the namespace 'ASP'.
Global.ASP.default_aspx.__initialized = true
~~~~~~~~~~~~~~~~~~~~~~~
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\ocbuild\c0c442ff\f0292c99\App_Web_default.aspx.cdcab7d2.4ubu1wgu.0.vb(76) : error BC30560: 'default_aspx' is ambiguous in the namespace 'ASP'.
Private Sub __BuildControlTree(ByVal __ctrl As default_aspx)
~~~~~~~~~~~~
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\ocbuild\c0c442ff\f0292c99\App_Web_default.aspx.cdcab7d2.4ubu1wgu.0.vb(100) : error BC30560: 'default_aspx' is ambiguous in the namespace 'ASP'.
Me.AddWrappedFileDependencies(Global.ASP.default_aspx.__fileDependencies)
~~~~~~~~~~~~~~~~~~~~~~~
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\ocbuild\c0c442ff\f0292c99\App_Web_default.aspx.cdcab7d2.4ubu1wgu.1.vb(31) : error BC30560: 'default_aspx' is ambiguous in the namespace 'ASP'.
Return New ASP.default_aspx
~~~~~~~~~~~~~~~~
I checked a few things and all of them turned out to be okay:
[*] Default is not defined twice
anywhere
[*] Everything was working
on the last release 1 week back
[*] There are no old files that are
still staying with the compiled
files. Also I cleared the temporary
files many times.
[*] I have tried
with other aspx files and all of
them is giving ambiguous error
(error in different source files...)
[*] The original source works just
fine! only the error shows up on the
compiled code.
Any ideas or any clues on how to resolve this ambiguity.
Thanks
SK

Answer 1

I just solved this problem with the assistance following link: http://www.netomatix.com/development/usercontrols2.aspx
Add this on aspx or ascx page ClassName="MyModule"
<%# Control Language="vb" AutoEventWireup="false" CodeBehind="MyModule.ascx.vb" ClassName="MyModule" %>

Answer 2

Okay here is what I found after spending three days on this problem.
Finally I figured that if I removed all the projects from the solution except one (that was causing problem) I could isolated it to default.skin. The problem seemed to be very erratic because it started going away if I deleted certain lines from this file. However, this was not consistent and the problem came and went at random.
So after losing all hopes of fixing it in the code, I decided to try it another way. I changed the option of aspnet_compiler command from -prefix switch (a dll is created for each folder) to -o (all compiled ui is put in one dll), the problem went away!!!
It seems that the problem is due to some bug in the aspnet_compiler. It got triggered in this version somehow that I could not figure out.
I am thinking of moving to more stable asp.net 3.5SP1 (or maybe wait for asp.net 4.0) any suggestions?

Answer 3

I ran into this issue in consuming project when changing name/namespace of a library that consuming project referenced.
Issue is consuming project Bin folder has copy of DLL with each name/namespace name.
Deleting the consuming project Bin folder and rebuilding solved.

Answer 4

I've found that mixing Namespaces can really confuse things.
The best way to clean it up is to remove all the namespace declarations in your web project, and make sure that they're consistent in dependent projects. Don't forget to check the project properties, and the generated .designer.vb files.
Also, it sounds like you have a top-level directory named ASP - that's probably not helping things either. I'd get rid of that directory entirely, and see if that helps the problem. I did report this as a bug to MS a while back, and even provided them with a reproducible example, but never heard anything back from them.

Answer 5

I solved this problem by putting the namespace above the class
Namespace yournamespace
Public Class yourclass name
end class
end Namespace

Answer 6

You need to make sure that the user control is also copied across with the page to your test server.

Answer 7

We had the same problem on out test servers. We found a duplicate of our application dll in the bin file. It's name was slightly different (missing a single "." in it) than the original dll but it contained the same types. We removed it and everything started working again.

Answer 8

After I checked the same items as Samuel:
[*] Default is not defined twice anywhere
[*] Everything was working on other computer 1 week back
[*] There are no old files that are still staying with the compiled files. Also I cleared the temporary files many times.
[*] I have tried with other aspx files and all of them is giving ambiguous error (error in different source files...)
[*] The original source works just fine! only the error shows up on the compiled code.
(...)
I just let my code as originaly in VS-2015 and in CMD window I executed:
C:\Windows\Microsoft.NET\Framework\v4.0.30319>aspnet_compiler -v / -p "C:\inetpub\wwwroot\projectFolder"
And every thing was running Ok without any error.
Subsequents compilations in VS-2015 environment were also Ok.