Prbolem with "enable-migrations"

Question

Hi,
I am new to APS.NET and I learning it. I have created an ASP. NET MVC project and I have added a class library to it. When I run "enable-migrations" I get this error:

ystem.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.IO.FileLoadException: Could not load file or assembly 'ClassLibrary2, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515) ---> System.NotSupportedException: An attempt was made to load an assembly from a network location which would have caused the assembly to be sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enable CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please enable the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=155569 for more information.

--- End of inner exception stack trace ---
at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
at System.Reflection.Assembly.Load(AssemblyName assemblyRef)
at System.Data.Entity.Infrastructure.Design.Executor..ctor(String assemblyFile, IDictionary`2 anonymousArguments)
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark)
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
at System.Activator.CreateInstance(String assemblyString, String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, Evidence securityInfo, StackCrawlMark& stackMark)
at System.Activator.CreateInstance(String assemblyName, String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
at System.AppDomain.CreateInstance(String assemblyName, String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
at System.AppDomain.CreateInstanceAndUnwrap(String assemblyName, String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
at System.AppDomain.CreateInstanceAndUnwrap(String assemblyName, String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
at System.Data.Entity.Tools.AppDomainExecutor..ctor(String assembly, String dataDirectory, String configurationFile, String rootNamespace, String language)
at System.Data.Entity.Tools.Commands.ProjectCommandBase.CreateExecutor()
at System.Data.Entity.Tools.Commands.MigrationsEnableCommand.Execute()
at Microsoft.DotNet.Cli.CommandLine.CommandLineApplication.Execute(String[] args)
at System.Data.Entity.Tools.Program.Main(String[] args)
Exception has been thrown by the target of an invocation.

Answer 1

The error message indicates that you're attempting to run to load the ClassLibrary2 assembly from a network location such as a UNC path. This is not supported. You need to ensure that the files are located on a local drive otherwise they cannot be loaded.

Answer 2

Hi @Smko ,

System.NotSupportedException: An attempt was made to load an assembly from a network location which would have caused the assembly to be sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enable CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please enable the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=155569 for more information.

The reason for this error should be that the Assembly file is intercepted by Windows.
You can resolve it by right clicking on the assembly file and selecting properties. In the Properties dialog box, click the Unblock button under the General tab, then click Apply and OK.
Or as the error says:
If this loading is not intended for sandboxed assemblies, enable the loadFromRemoteSources switch.
Add the following flags in your configuration file or use Assembly.UnsafeLoadfrom.
https://learn.microsoft.com/en-us/dotnet/framework/configure-apps/file-schema/runtime/loadfromremotesources-element
https://learn.microsoft.com/en-us/dotnet/api/system.reflection.assembly.unsafeloadfrom?view=net-7.0

<configuration>  
   <runtime>  
      <loadFromRemoteSources enabled="true"/>  
   </runtime>  
</configuration>  

Best regards,
Lan Huang

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