DevForce 2010: Design-time problem

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Design-time problem

Printed From: IdeaBlade
Category: DevForce
Forum Name: DevForce 2010
Forum Discription: For .NET 4.0
URL: http://www.ideablade.com/forum/forum_posts.asp?TID=3247
Printed Date: 13-May-2026 at 1:03am

Topic: Design-time problem

Posted By: samir
Subject: Design-time problem
Date Posted: 01-Feb-2012 at 6:43am

Hello.

I´m trying to instantiate an Entity Manager during design-time but I get this error:

Attempt by security transparent method 'DynamicClass.ReadImaginePulseTaskFromXml(System.Runtime.Serialization.XmlReaderDelegator, System.Runtime.Serialization.XmlObjectSerializerReadContext, System.Xml.XmlDictionaryString[], System.Xml.XmlDictionaryString[])' to access security critical type 'ImaginePulse.Models.ImaginePulseTask' failed.

Assembly 'System.Runtime.Serialization, Version=5.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' is marked with the AllowPartiallyTrustedCallersAttribute, and uses the level 2 security transparency model. Level 2 transparency causes all methods in AllowPartiallyTrustedCallers assemblies to become security transparent by default, which may be the cause of this exception.

Do you have any idea how can I solve this error?

Thanks,

Samir

Replies:

Posted By: kimj
Date Posted: 01-Feb-2012 at 11:28am

Hi Samir,

We haven't seen this particular design-time error with Silverlight 5 before, but we have seen others (which I mention below). There are a few things you can try:

- Ensure your assembly has an InternalsVisibleTo attribute specifying System.Runtime.Serialization. We generate this automatically in Silverlight application projects (in AssemblyInfo.cs), so if your model project doesn't already include it you can copy the attribute from one that does.

- If the above doesn't work add the AllowPartiallyTrusedCallers attribute to your assembly.

Now for the SL5 design-time errors we've run into. Even should you get the above working, we've seen problems with using an EntityCacheState at design time, and with adding or attaching entities to an EntityManager. These problems will usually manifest as a MissingMethodException, and will occur in code that was working fine when only Silverlight 4 was installed. We don't yet have an answer for these problems, since Microsoft tells us they're caused by designer dependencies on .NET 4.5.

If you do run into additional problems, we have found that creating entities, but not attaching or adding them to an EntityManager, does work.

Posted By: blogger
Date Posted: 21-Sep-2012 at 10:02am

Posted By: kimj
Date Posted: 21-Sep-2012 at 10:57am

Yes, this "Method not found" problem is one we've seen when using an EntityCacheState at design time.

We don't have any fixes for this, and the best advice I can give right now is not to use the ECS at design time. You can create detached entities, or create and attach them to an EntityManager if you wish to retrieve them from the EM cache.

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