Namespace or type specified in project level imports does not contain a public member

I have an ASP.NET 3.5 web application project in which I'm trying to implement a searchable gridview. I originally started the project as a web site and converted it to a web application. After conversion, my class ended up in the fo开发者_JAVA技巧lder Old_App_Code and is called SearchGridView.vb.

Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Text
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Drawing.Design


<Assembly: TagPrefix("MyApp.WebControls", "SearchGridView")> 
Namespace MyApp.WebControls
#Region "TemplateColumn"
Public Class NumberColumn
Implements ITemplate

   Public Sub InstantiateIn(ByVal container As System.Web.UI.Control) Implements     System.Web.UI.ITemplate.InstantiateIn

   End Sub
   End Class
   #End Region
   <ToolboxData("<{0}:SearchGridView runat=server></{0}:SearchGridView>")> _
   <ParseChildren(True, "SearchFilters")> _
   Public Class SearchGridView
   Inherits GridView

The class file continues, but this is the first part of it.

Unfortunately, I receive the error message Warning 1 Namespace or type specified in the project-level Imports 'MyApp.WebControls' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases. DielWebProj

In web.config, I included a namespace tag for MyApp.WebControls and I included an imports tag in the .aspx page as well.

Can anyone shed light as to why this error is being raised and how I would remedy it?

Thanks, Sid

I have a broadly similar problem to you. I have a website project using a custom control, inheriting from GriView, in the app_code folder. I was recieving the very same error, but noted that it happened only after I would add a second class or module to app_code, and would disappear if I removed it.

So the workaround I have at the moment is to just leave my custom control as the sole occupant of app_code.

One option might be to make the control part of its own project and add it as a reference to the we site/app?

I'll update this if I can find a decent solution.

EDIT: Well, in my case it was because the control I was using was written in C#, whereas the rest of the project, and classes I added to app_code, were in VB. The app_code folder is compiled to a single assembly, so classes of different languages cannot share it, unless you create seperate sub-folders and do some config file jiggerypokery. More details here