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Fed Up With System.Data.Metadata.Edm.ObjectItemAssemblyLoader

Posted By: Ken Cox [MVP]     Posted Date: August 26, 2010    Points: 0   Category :ASP.Net
I'm fed up with the random errors I'm getting on my ASP.NET 4, Entity Framework 4 web application lately. It seems to stem from something that System.Data.Metadata.Edm is doing with a call to System.Reflection.Assembly.GetTypes(). I keep getting the error that I complained about previously : Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information. To display those Loader exceptions, I added the following to my global.asax file: Sub Application_Error...(read more)

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The type 'System.Data.Linq.DataContext' is defined in an assembly that is not referenced. You must



This is frustrating, and I don't know how to solve it.

I have a strange problem. I am adding a LinqDatasource object, and set the context:

        protected void LinqDataSource_ContextCreating(object sender, LinqDataSourceContextEventArgs e)
            e.ObjectInstance = new KaruselaDataContext(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);

Then I get this error:
The type 'System.Data.Linq.DataContext' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Data.Linq, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089'.


On web.config I already have this:
<add assembly="System.Data.Linq, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>

NOTE: The datacontext is in a different project (DLL proect) where I added a refernce to System.Data.Linq.

is there another way adding a refernce to a web project? or only though teh web.config?


Compiler Error Message : CS0006: Metadata file 'System.EnterpriseServices.dll' could not be found


I get this error when i Debug my web application....


I followed these steps.,

  • Ended the aspnet_wp.exe process in the Windows Task Manager
  • Then deleted the application`s folder in C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\
  • Then started Visual Studio 2008 again

I also rebooted my system but no use....

Plz help !

Data Points: Revisiting System.Transactions


The System.Transactions namespace of the Microsoft .NET Framework makes handling transactions much simpler than previous techniques. Read all about it this month.

John Papa

MSDN Magazine November 2006

Data Points: ADO.NET and System.Transactions


The Microsoft® . NET Framework versions 1. 0 and 1. 1 represented major changes in software development. However, one important thing that did not change much was support for distributed transactions.

John Papa

MSDN Magazine February 2005

Metadata: Create a Database Schema Repository with Meta Data Services in SQL Server 2000


SQL Server 2000 Meta Data Services is a repository technology that stores and manages metadata for SQL Server. Instead of building database schemas over and over, Meta Data Services allows you to freeze an entire schema for use in other projects. You can also use these schemas for training, testing, or debugging. In this article, the authors will review the various components of Meta Data Services and show how it can be programmed using a Visual Basic client, XML, and XSLT. They will also show you how to manage and manipulate your metadata by generating a simple database schema using a SQL Server repository.

Alok Mehta and Ricardo Rodriguez

MSDN Magazine May 2003

Exchange 2000 WSS: Web Storage System Improves Exchange Data Accessibility


The Web Storage System (WSS) in Exchange 2000 is a Web-accessible database that stores any type of data such as e-mail, contacts, appointments, threaded discussions, and multimedia files, and renders the data in HTML in any browser. WSS is based on Internet standards, therefore data can be accessed through URLs, an Exchange OLE DB provider, drive mapping, XML, and Web Documenting and Versioning (WebDAV). This article discusses the WSS schema and how to extend the default schema for custom data. A sample application that uses a custom schema and a custom form to display WSS data is available for download.

Sean McCormick

MSDN Magazine May 2001

Which ComponentModel.DataAnnotations attributes are used in the Dynamic Data metadata classes?


This namespace contains a lot of attributes for use in, I'm sure, many different applications. I'm curious to know which subset of the attributes in this namespace can be and are used in the Dynamic Data proxy class system, where the entity class is given an attribute that specifies a metadata type. That type contains properties with the same names as properties in the entity class, and the metadata provider builds MetaColumns using attributes on properties in these 'buddy' (proxy') classes.

So far my list includes, from System.ComponentModel.DataAnnotations:

Required, Range, DisplayFormat, StringLength, UIHint, DataType, Regular Expression, Display Column, Editable, and CustomValidation.

And from System.ComponentModel:

DisplayName, Description, and DefaultValue.

Am I missing any?

This was originally asked by myself on StackOverflow at: http://stackoverflow.com/questions/3537356/which-componentmodel-dataannotations-attributes-are-used-in-the-dynamic-data-meta

Business Data Error: System.OverFlowException


I have a Business Data Catalog file I've uploaded to connect to our back end Firebird DBMS through ODBC.

The SharePoint server is MOSS 2007 x64. The web front end server(s) all have an x64 Firebird Engine and ODBC driver with verified connectivity to Firebird.

When I use one of the methods, I can see connections being made to our Firebird server and the query being passed. I know the query returns results (it's a stored procedure with no parameters), but I get the following error "An error occurred while retrieving data from MROTest1. Administrators, see the server log for more information" in IE. If I look in the server logs, I see (12\Hive\Logs)

Exception handed to HandleRuntimeException.HandleException System.OverflowException: Arithmetic operation resulted in an overflow.     at System.Data.Odbc.OdbcDataReader.GetData(Int32 i, SQL_C sqlctype, Int32 cb, Int32& cbActualOut)

System.Data.SqlClient.SqlException: Login failed for user . Reason: The account is disable


Hi All,

Thank you for advance.

I created a widows service for mail schedule with c#.net and sql server 2005 and it is working fine for past one year.

now sometimes i am getting the "System.Data.SqlClient.SqlException: Login failed for user '<UserName>'. Reason: The account is disabled." error.

then i restarted the windows service manually and working.

what is the problem in my sql server connection and how to fix that issue?

System.InvalidOperationException: Invalid attempt to read when no data is present.


Invalid attempt to read when no data is present.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.InvalidOperationException: Invalid attempt to read when no data is present.

Source Error: 

Line 53:             if (reader.HasRows)
Line 54:             {
Line 55:                 Response.Write(reader.GetString(0));

Here is my code:

System.Data.OleDb.OleDbException: Could not find installable ISAM.


Hi, i got the following error while i am trying to get my web application to run on windows server 2003. I've installed 2007 data access components on windows server 2003 but the web application does not seem to work. The codes that i use is as follows:

string strConn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + address + ";Extended Properties=Excel 12.0;"; OleDbConnection objConn = new OleDbConnection(strConn); string strSQL = "SELECT * FROM [Sheet 1$]"; OleDbCommand objCmd = new OleDbCommand(strSQL, objConn);

OleDbDataReader oddReader = null;


oddReader = objCmd.ExecuteReader();







I've read a lot of forum posts and almost all of them mentioned ab out the connectionstring being wrong. However, when i ran the codes on my local machine, there were no errors. The error only show when i was running on windows server 2003.

I've underlined where the error is pointing to. Please advise. Thanks

CheckedListBox displays System.Data.DataRowView on one machine

As I was writing this post I solved my problem. Now I will share the solution for anyone who may stumble across this legacy cr*p. I inherited an old VB.NET application written in the old Visual Studio .Net against the 1.0 framework. Recently we had to rebuild a couple of machines and redeploy the app. We have CheckedListBox controls bound using the DataSource property and suddenly all we could see was System.Data.DataRowView in the list on these machines. All the forums out there tell you that binding the items with the DataSource property is not supported by Microsoft and offer code fixes, which we obviously do not want to do. I installed the .Net Framework 1.0 redistributable and fixed it right up. Which is a little strange because one of the machines it still works on only has 1.1. But there you have it  I actually tested this on another machine by installing 1.1 first, which did not fix the problem, but installing 1.0 did. And another interesting thought. The executable and its class library dependency reside in a network share. After installing the 1.0 framework I had to run a Caspol.exe command to grant privs to the share or the executable could not access the library. The app functioned fine without the Caspol.exe command (except the ListBox of course) prior to installing the 1.0 framework. Strange stuff...Hope this helps someone someday.

Add System.Data.SqlServerCE

Hi I have a web application using visual studio 2005 and i want to use the namespaces System.Data.SqlServerCe on my asp.net page. But i couldnt find the the dll from the AddReference Dialog. Please help!!!!   Regards, LINOO   

System.IO.IOException: Unable to read data from the transport connection

Hello,   I have an xml webservice calling another xml web service and occasionally i get the following error - any ideas why?Does this happen when the request is made or when reading the response? Also how i can prevent it from happening? Thanks   System.IO.IOException: Unable to read data from the transport connection: A blocking operation was interrupted by a call to WSACancelBlockingCall. ---> System.Net.Sockets.SocketException: A blocking operation was interrupted by a call to WSACancelBlockingCall   at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)   at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)   --- End of inner exception stack trace ---   at System.Net.ConnectStream.Read(Byte[] buffer, Int32 offset, Int32 size)   at System.IO.StreamReader.ReadBuffer(Char[] userBuffer, Int32 userOffset, Int32 desiredChars, Boolean readToUserBuffer)   at System.IO.StreamReader.Read(Char[] buffer, Int32 index, Int32 count)   at System.Xml.XmlTextReaderImpl.ReadData()   at System.Xml.XmlTextReaderImpl.InitTextReaderInput(String baseUriStr, TextReader input)   at System.Xml.XmlTextReaderImpl..ctor(String url, TextReader input, XmlNameTable nt)   at System.Xml.XmlTextReader..ctor(TextReader input)   at System.Web.Services.Protocols.SoapHttpClientProtocol.GetReaderForMessage(SoapClientMessage message, I

Data access from Remote system throwgh webservice

Hi, i wrote the webservice and configured in our server and having access the service through the browser from another system also working fine, But i am trying to access the service through in my application creating the proxy and accessing methods of the webservice, but it can't get the data from  the remote sqlserver through the webservice.    this is for my connection string  in  web config:   <add key="ConnectionString" value="server=EVEREST;initial catalog=MRMv1;uid=sa;pwd=kk"/>   the following the error was shown to me: Server was unable to process request. ---> Login failed for user 'sa' but i can login to sqlserver using 'sa' user in the remote server. how can i get the data from the remote server.        can you please guide to me. thanks and regards brite

System.Security.SecurityException: Request for the permission of type 'System.Data.SqlClient.SqlCli

I have created a windows library control that accesses a local sql database I tried the following strings for connecting Dim connectionString As String = "Data Source=localhost\SQLEXPRESS;Initial Catalog=TimeSheet;Trusted_Connection = true" Dim connectionString As String = "Data Source=localhost\SQLEXPRESS;Initial Catalog=TimeSheet;Integrated Security=SSPI"   I am not running the webpage in a virtual directory but in C:\Inetpub\wwwroot\usercontrol and I have a simple index.html that tries to read from an sql db but throws the error System.Security.SecurityException: Request for the permission of type 'System.Data.SqlClient.SqlClientPermission, System.Data, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.   at System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet)   at System.Security.PermissionSet.Demand()   at System.Data.Common.DbConnectionOptions.DemandPermission()   at System.Data.SqlClient.SqlConnection.PermissionDemand()   at System.Data.SqlClient.SqlConnectionFactory.PermissionDemand(DbConnection outerConnection)   at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, etc etc  The action that failed was:DemandThe type of the first permission that failed was:System.Data.SqlClient.SqlClientPermissionThe Zone of the assembly that fa

System.Data.SqlClient.SqlException: Bulk load data was expected but not sent

Hi everyone We've had this error twice now from our C# code. Nothing is changing the columns, but I've noticed though that it appears to happen when two threads are attempting to bulk insert into the same table, generally millions of rows. The docs say that SqlBulkCopy.WriteToServer is not guaranteed to be thread-safe, but is this the problem here? It feels like it. I've seen some posts where people appeared to have experienced problems in similar circumstances (http://social.msdn.microsoft.com/forums/en-US/sqldatabaseengine/thread/85d51484-6381-46bc-bcce-63b58b362d2d). There is no identity column just a non-unique clustered index that is (spid) process keyed to each thread. Do I need to synchronise access to the table for WriteToServer - is this a known problem? Many thanks Reg --- System.Data.SqlClient. SqlException: Insert bulk failed due to a schema change of the target table.   at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)   at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)   at System.Data.SqlClient.SqlBulkCopy.WriteToServerInternal()   at System.Data.SqlClient.SqlBulkCo
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