We recently migrated our ASP.NET web application from .NET 3.5 to 4.0.
After migration there is no intellisense for our web user controls and therefore we can not add event handlers in the page using the user control.
The same with newly created user controls (we drag and dropped the user controls in the page).
Visual Studio 2012 shows the following compiler warning:
Element 'TestWebUserControl1' is not a known element. This can occur if there is a compilation error in the Web site, or the web.config file is missing.
Web User Control:
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="TestWebUserControl1.ascx.cs" Inherits="sMatSupervisor.TestWebUserControl1" %>
using System;
namespace sMatSupervisor
{
public partial class TestWebUserControl1 : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
}
}
}
Test page:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="TestForm.aspx.cs" Inherits="sMatSupervisor.TestForm" %>
<%@ Register Src="~/TestWebUserControl1.ascx" TagPrefix="uc1" TagName="TestWebUserControl1" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<uc1:TestWebUserControl1 runat="server" id="TestWebUserControl1" />
</div>
</form>
</body>
</html>
using System;
namespace sMatSupervisor
{
public partial class TestForm : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
}
}
Web.config:
<?xml version="1.0" encoding="utf-8"?>
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
<configSections>
</configSections>
<connectionStrings configSource="connections.config" />
<appSettings file="global.config">
</appSettings>
<system.web>
<compilation debug="true">
<assemblies>
<add assembly="System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add assembly="System.ServiceModel.Activation, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add assembly="System.Runtime.Serialization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Web.ApplicationServices, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
<add assembly="System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
<add assembly="System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Xml, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Web.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
<add assembly="System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
<add assembly="System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.ServiceModel.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add assembly="System.Data.Services.Client, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Data.Services.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
</assemblies>
</compilation>
<pages>
<controls>
<add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" />
</controls>
</pages>
</system.web>
<system.webServer>
<httpRedirect enabled="false" />
</system.webServer>
</configuration>
Here is the solution add targetFramework="4.0" to compilation tag in Web.config:
It was missing targetFramework = "4.0".
Solution found in System.Web.UI.ScriptManager' is defined in an assembly that is not referenced. But it is in the assembly?