EFCore + LazyLoadingProxies + Localization + Html.DisplayNameForModel() == NotSupportedException: The invoked member is not supported in a dynamic asm

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

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I'm using EFCore with SQL Server + Lazy Loading. I also use @Html.DisplayNameForModel() to display the model's name in Views. Recently I added localization and now calling @Html.DisplayNameForModel() will cause the following exception,

System.NotSupportedException: The invoked member is not supported in a dynamic assembly.
   at System.Reflection.Emit.InternalAssemblyBuilder.GetManifestResourceStream(Type type, String name)
   at System.Resources.ManifestBasedResourceGroveler.GrovelForResourceSet(CultureInfo culture, Dictionary`2 localResourceSets, Boolean tryParents, Boolean createIfNotExists)
   at System.Resources.ResourceManager.InternalGetResourceSet(CultureInfo culture, Boolean createIfNotExists, Boolean tryParents)
   at System.Resources.ResourceManager.GetString(String name, CultureInfo culture)
   at Microsoft.Extensions.Localization.ResourceManagerStringLocalizer.GetStringSafely(String name, CultureInfo culture)
   at Microsoft.Extensions.Localization.ResourceManagerStringLocalizer.get_Item(String name)
   at Microsoft.AspNetCore.Mvc.DataAnnotations.DataAnnotationsMetadataProvider.<>c__DisplayClass9_0.b__4()
   at Microsoft.AspNetCore.Mvc.ModelBinding.Metadata.DefaultModelMetadata.get_DisplayName()
   at Microsoft.AspNetCore.Mvc.ViewFeatures.HtmlHelper.GenerateDisplayName(ModelExplorer modelExplorer, String expression)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.HtmlHelper.DisplayName(String expression)
   at Microsoft.AspNetCore.Mvc.Rendering.HtmlHelperDisplayNameExtensions.DisplayNameForModel(IHtmlHelper htmlHelper)
   at AspNetCoreGeneratedDocument.Views_MyModels_Edit.ExecuteAsync() in C:\Users\tspoh\source\repos\EFCoreLocalizationDisplayNameForModelBug\EFCoreLocalizationDisplayNameForModelBug\Views\MyModels\Edit.cshtml:line 10
   at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageCoreAsync(IRazorPage page, ViewContext context)
   at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderPageAsync(IRazorPage page, ViewContext context, Boolean invokeViewStarts)
   at Microsoft.AspNetCore.Mvc.Razor.RazorView.RenderAsync(ViewContext context)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, String contentType, Nullable`1 statusCode)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ViewContext viewContext, String contentType, Nullable`1 statusCode)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewExecutor.ExecuteAsync(ActionContext actionContext, IView view, ViewDataDictionary viewData, ITempDataDictionary tempData, String contentType, Nullable`1 statusCode)
   at Microsoft.AspNetCore.Mvc.ViewFeatures.ViewResultExecutor.ExecuteAsync(ActionContext context, ViewResult result)
   at Microsoft.AspNetCore.Mvc.ViewResult.ExecuteResultAsync(ActionContext context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|30_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|25_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|20_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Microsoft.AspNetCore.Localization.RequestLocalizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

I am able to replicate the issue and I'm attaching a small project to reproduce it. Open, run and follow steps,

1. Click "Test Bug"
2. Click "Create New" => OK
3. Click "Edit", "Details", or "Delete" => Exception

I noted that the following combination caused the exception,

1. EF Core + LazyLoading + Localization + Html.DisplayNameForModel().

The following combinations are ok,

1. EF Core + LazyLoading + Html.DisplayNameForModel().
2. EF Core + Localization + Html.DisplayNameForModel().

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Original Comments

Feedback Bot on 8/3/2022, 00:47 AM:

(private comment, text removed)

Nicholas Poh on 8/3/2022, 04:32 AM:

(private comment, text removed)

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Original Solutions

Nicholas Poh solved on 8/4/2022, 09:36 PM, 0 votes:

The workaround is to introduce a new extension for IHtmlHelper

public static string DisplayNameForModelEx(this IHtmlHelper html)
{
    var serviceProvider = html.ViewContext.HttpContext.RequestServices;
    var modelType = html.ViewData.Model.GetType();
    return GetDisplayName(modelType, serviceProvider);
}
private static string GetDisplayName(this Type type, IServiceProvider serviceProvider = null)

{

string result = null;
<span class="hljs-keyword">if</span> (type.Namespace.Equals(<span class="hljs-string">"Castle.Proxies"</span>))
{
    type = type.BaseType;
}

<span class="hljs-keyword">var</span> dnAttributes = GetCustomAttributes&lt;DisplayNameAttribute&gt;(type);
<span class="hljs-keyword">if</span> (dnAttributes?.Length &gt; <span class="hljs-number">0</span>)
{
    result = dnAttributes.First().DisplayName;
}

<span class="hljs-keyword">if</span> (result == <span class="hljs-literal">null</span>)
{
    <span class="hljs-keyword">var</span> dAttributes = GetCustomAttributes&lt;DisplayAttribute&gt;(type);
    <span class="hljs-keyword">if</span> (dAttributes?.Length &gt; <span class="hljs-number">0</span>)
    {
        result = dAttributes.First().Name;
    }
}

<span class="hljs-keyword">if</span> (result == <span class="hljs-literal">null</span>)
{
    result = type.Name;
}

<span class="hljs-keyword">if</span> (serviceProvider != <span class="hljs-literal">null</span>)
{
    <span class="hljs-keyword">var</span> genericType = <span class="hljs-keyword">typeof</span>(IStringLocalizer&lt;&gt;);
    <span class="hljs-keyword">var</span> listOfTypeArgs = <span class="hljs-keyword">new</span>[] { type };
    <span class="hljs-keyword">var</span> serviceType = genericType.MakeGenericType(listOfTypeArgs);
    <span class="hljs-keyword">if</span> (serviceProvider.GetService(serviceType) <span class="hljs-keyword">is</span> IStringLocalizer localizer)
    {
        <span class="hljs-keyword">return</span> localizer[result];
    }
}

<span class="hljs-keyword">return</span> result;

}
private static T[] GetCustomAttributes<T>(Type type)

where T : Attribute

{

return (T[])(object)type.GetCustomAttributes(typeof(T), false);

}

Replace @Html.DisplayNameForModel() with @Html.DisplayNameForModelEx()

[programatix]

Let me re-format the workaround posted above,

public static string DisplayNameForModelEx(this IHtmlHelper html)
{
    var serviceProvider = html.ViewContext.HttpContext.RequestServices;
    var modelType = html.ViewData.Model.GetType();
    return GetDisplayName(modelType, serviceProvider);
}

private static string GetDisplayName(this Type type, IServiceProvider serviceProvider = null)
{
    string result = null;

    if (type.Namespace.Equals("Castle.Proxies"))
    {
        type = type.BaseType;
    }

    var dnAttributes = GetCustomAttributes<DisplayNameAttribute>(type);
    if (dnAttributes?.Length > 0)
    {
        result = dnAttributes.First().DisplayName;
    }

    if (result == null)
    {
        var dAttributes = GetCustomAttributes<DisplayAttribute>(type);
        if (dAttributes?.Length > 0)
        {
            result = dAttributes.First().Name;
        }
    }

    if (result == null)
    {
        result = type.Name;
    }

    if (serviceProvider != null)
    {
        var genericType = typeof(IStringLocalizer<>);
        var listOfTypeArgs = new[] { type };
        var serviceType = genericType.MakeGenericType(listOfTypeArgs);
        if (serviceProvider.GetService(serviceType) is IStringLocalizer localizer)
        {
            return localizer[result];
        }
    }

    return result;
}

private static T[] GetCustomAttributes<T>(Type type)
    where T : Attribute
{
    return (T[])(object)type.GetCustomAttributes(typeof(T), false);
}

[programatix]

Since I posted the workaround above on 3rd Aug, I found a problem in DisplayNameForModelEx. The updated function should be as follow,

public static string DisplayNameForModelEx(this IHtmlHelper html)
{
    var serviceProvider = html.ViewContext.HttpContext.RequestServices;
    var modelType = html.ViewData.ModelExplorer.ModelType;
    if (modelType.IsArray)
    {
        modelType = modelType.GetElementType();
    }
    else if (modelType.IsGenericType && modelType.GenericTypeArguments.Length > 0)
    {
        // This is just a quick one. Should improve this by perhaps concatenate all of them.
        modelType = modelType.GenericTypeArguments.First();
    }
    return modelType.GetDisplayName(serviceProvider: serviceProvider);
}

Two things are updated.

• html.ViewData.Model can be null at times, so replaced with html.ViewData.ModelExplorer.
• Added a check for Array and get's the actual Type instead.

[halter73]

@jkotas Could this be a dupe of dotnet/runtime#67802?

[jkotas]

This is not a dup of dotnet/runtime#67802. dotnet/runtime#67802 was about Assembly.Location property and Assembly.LoadFrom. This one is failing in GetManifestResourceStream.

I think that the root cause of the problem is that the localization middleware is looking for resources in a wrong place where there are no resources to be found.