In the web.config of webforms .net 4.5 application I set the following:
<trust legacyCasModel="true" level="Full" />
because this is a Microsoft work around to overcome an bug in the asp.net Report Viewer which causes large reports to take much longer to generate than in previous .net versions (3.5 and older). Unfortunately, enabling the legacy CasModel has caused the error below. As the error suggests I have attempted many times to apply an exception in my site's web.config such as:
<system.web>
<partialTrustVisibleAssemblies>
<add assemblyName="System.Web.Extensions" version="4.0.0" publicKey="0024000004800000940000000602000000240000525341310004000001000100B5FC90E7027F67871E773A8FDE8938C81DD402BA65B9201D60593E96C492651E889CC13F1415EBB53FAC1131AE0BD333C5EE6021672D9718EA31A8AEBD0DA0072F25D87DBA6FC90FFD598ED4DA35E44C398C454307E8E33B8426143DAEC9F596836F97C8F74750E5975C64E2189F45DEF46B2A2B1247ADC3652BF5C308055DA9" />
</partialTrustVisibleAssemblies>
</system.web>
But the error still occurs. I also attempted to apply this setting to the .net 4 web.config and specify this assembly to have full trust but it still won't work. I've read a ton of documentation pertaining to this issue and I cannot locate any other way this issue maybe resolved (except to remove this assembly in my project or make other major changes to my web application). Any suggestions of how I can fix or address this issue would be greatly appreciated, Thanks.
Server Error in '/' Application. Attempt by security transparent method 'Microsoft.ScriptManager.MSAjaxv45.PreApplicationStartCode.Start()' to access security critical method 'System.Web.UI.ScriptManager.get_ScriptResourceMapping()' failed. Assembly 'System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' is a conditionally APTCA assembly which is not enabled in the current AppDomain. To enable this assembly to be used by partial trust or security transparent code, please add assembly name 'System.Web.Extensions, PublicKey=0024000004800000940000000602000000240000525341310004000001000100B5FC90E7027F67871E773A8FDE8938C81DD402BA65B9201D60593E96C492651E889CC13F1415EBB53FAC1131AE0BD333C5EE6021672D9718EA31A8AEBD0DA0072F25D87DBA6FC90FFD598ED4DA35E44C398C454307E8E33B8426143DAEC9F596836F97C8F74750E5975C64E2189F45DEF46B2A2B1247ADC3652BF5C308055DA9' to the the PartialTrustVisibleAssemblies list when creating the AppDomain. 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.MethodAccessException: Attempt by security transparent method 'Microsoft.ScriptManager.MSAjaxv45.PreApplicationStartCode.Start()' to access security critical method 'System.Web.UI.ScriptManager.get_ScriptResourceMapping()' failed. Assembly 'System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' is a conditionally APTCA assembly which is not enabled in the current AppDomain. To enable this assembly to be used by partial trust or security transparent code, please add assembly name 'System.Web.Extensions, PublicKey=0024000004800000940000000602000000240000525341310004000001000100B5FC90E7027F67871E773A8FDE8938C81DD402BA65B9201D60593E96C492651E889CC13F1415EBB53FAC1131AE0BD333C5EE6021672D9718EA31A8AEBD0DA0072F25D87DBA6FC90FFD598ED4DA35E44C398C454307E8E33B8426143DAEC9F596836F97C8F74750E5975C64E2189F45DEF46B2A2B1247ADC3652BF5C308055DA9' to the the PartialTrustVisibleAssemblies list when creating the AppDomain.
@Sachin, thank you for your answer however I need those assemblies for this project so that would not resolve this issue. I resolved this issue a while ago. I think this error was occurring when attempting some authentication functions in the application. I resolved the issue by setting the report function to open in a new application pool, so that the enabling of the legacy CAS model only effects the new application pool and therefore not effecting other authentication functions in the application.