Exception in constructor of object context

Thu, 18 Dec 2008 22:07:48 Z

I setup an object context, but when I instantiate it, I get an execption.

Here is when the error occurs (in auto-generated code):

public MySilverEntities(string connectionString) :

base(connectionString, "MySilverEntities")

{

this.OnContextCreated();

}
Here is the exception
System.NotSupportedException occurred
Message="The invoked member is not supported in a dynamic assembly."
Source="mscorlib"
StackTrace:
at System.Reflection.Emit.AssemblyBuilder.GetManifestResourceNames()
InnerException:
However, after the excpetion normal execute occurs, meaning that the exception is caught in the base class.

Any suggestions?

Thank you

Sergey.

Sergey

Exception in constructor of object context

Fri, 03 Jul 2009 16:16:01 Z

Sergey, have you solved the problem or find a workaround solution? I've seen the same exception occurring in my generated code. I'm looking for a workaround....

Thanks
Bobby

Exception in constructor of object context

Sat, 04 Jul 2009 07:23:32 Z

Can you give a stack trace?

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Exception in constructor of object context

Mon, 06 Jul 2009 12:21:24 Z

Edit: This error is ONLY thrown if you've explicitly told your debugger to break on CLR exceptions.

I just started getting this error, after starting to pass a modified connection string to the constructor. The weird thing is I'm now still getting the error even after rolling everything back to the previous code.

The error is thrown at any of the generated constructors:
public MyEntities(string connectionString) : base(connectionString, "MyEntities")
...or...
public MyEntities(global::System.Data.EntityClient.EntityConnection connection) : base(connectionString, "MyEntities")
...or...
public MyEntities() : base("name=MyEntities", "MyEntities")

The Stack Trace in its entirety is: at System.Reflection.Emit.AssemblyBuilder.GetManifestResourceNames()

Even after throwing the error, execution continues and everything works fine as long as you're not debugging.

The description for GetManifestResourceNames is illuminating:

public override string[] GetManifestResourceNames()
Member of System.Reflection.Emit.AssemblyBuilder

Summary:
Loads the specified manifest resource from this assembly.

Returns:
An array of type String containing the names of all the resources.

Exceptions:
System.NotSupportedException: This method is not supported on a dynamic assembly. To get the manifest resource names, use System.Reflection.Assembly .GetManifestResourceNames().
System.Security.SecurityException: The caller does not have the required permission.

Ash

Exception in constructor of object context

Tue, 07 Jul 2009 07:02:11 Z

By default the Entity Framework metadata artifacts are included as assembly resources and the connection string includes metadata path similar to "res://*/model.csdl;res://*/model.csdl;res://*/res.msl" when you build an EF application through VS. The "res://*" tells the EF runtime that the metadata files are in one of the referenced assemblies as an embedded resource. During runtime, EF tries to find the metadata resources by walking the referenced assemblies. But the above exception is hit if one of the assemblies in this list is a dynamic assembly. In this case, we catch the exception and continue since in .Net 3.5 we did not have a clean way to determine if an Assembly is Dynamic. But in .Net 4.0( VS 2010), a property has been added on Assembly class which can be used to determine if an assembly is a dynamic one. So this issue has been fixed in VS 2010 Beta 1 by checking if an assembly is dynamic before calling the GetManifestResourceNames method.
One way to work around the problem in VS 2008 is to change the metadata paths in the connection string to point to a specific assembly rather than *.
ex:

Metadata=res://AdventureWorks, 1.0.0.0, neutral, a14f3033def15840/model.csdl| 
res://AdventureWorks, 1.0.0.0, neutral, a14f3033def15840/model.ssdl| 
res://AdventureWorks, 1.0.0.0, neutral, a14f3033def15840/model.msl

Thanks
Srikanth

This posting is provided "AS IS" with no warranties, and confers no rights.