With each EF version there was a different way to get an underlying object for a proxy. None of the old tricks work using EF core 2.2. I referenced Castle.Core which EF uses and called ProxyUtil.GetUnproxiedInstance but that just returns the proxy again as already noted in below article. NONE of the suggestions there work. NOTE ! I need the instance, not the type which I can easily get via BaseType.
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I'm in the process of porting a Asp.Net Core Website targeting the full framework to a website that targets Asp.Net Core 3.
In that process I have hit a snag. The website references the Newtonsoft 11.0.3 NuGet package and among other things uses the Newtonsoft.Json.Serialization.DynamicValueProvider class.
Interestingly that class exists when targeting the full framework but does not exist when targeting netcoreapp3.1 and so Visual Studio is producing compilation errors stating that the class doesn't exist. At first that seemed crazy to me, but I checked the source code for the class and sure enough it contains the following conditional compilation statement wrapped around the whole class
#if HAVE_REFLECTION_EMIT
Apparently the netStandard 2.0 dll in the NuGet package that my netcoreapp3.1 project would use causes the conditional compilation statement to not include the DynamicValueProvider class.
So I did some poking around in the Newtonsoft.Json.Serialization namespace and I see that there is a ReflectionValueProvider class available that does not contain such conditional compilation and is available when targeting netcoreapp3.1
I've looked at the source code for both the DynamicValueProvider class and the ReflectionValueProvider class and I'm unclear on the difference. Both appear to get or set the value of a property or member type based on the MemberInfo passed in into the constructor. Both appear to use reflection to accomplish their work. As I mentioned, apparently DynamicValueProvider needs reflection Emit ability and ReflectionValueProvider does not. Emit ability apparently is used to Emit IL as best I can tell.
So I wonder if perhaps the two are drop in replacements for each other except that maybe DynamicValueProvider might be faster since it apparently leverages IL Emitting. But that's just a hunch. I'd prefer to have a more concrete understanding of the differences between the two classes before I start swapping the one for the other in this existing codebase as a way to get to .Net Core 3.
Can you provide me with better insight into the differences between the DynamicValueProvider
class and the ReflectionValueProvider class, or at least confirm my hunch?
We had updated Newtonsoft.Json from 9.* to 12.0.3 version, and observed performance degradation on paths that includes json serialization. All paths lead to DynamicValueProvider. Fortunately, we had global descendant for DefaultContractResolver, and I was able to overload CreateMemberValueProvider method to return ReflectionValueProvider.
For now we are continue testing the new version, but I can say that from performance perspective ReflectionValueProvider works faster than DynamicValueProvider.
I think there is a correlation with the fact that NetStandard 2.0 is also used to build Xamarin.Forms applications for iOS which require an AOT compilation.
As written here:
Limitations of Xamarin.iOS
"Since applications using Xamarin.iOS are compiled to static code, it is not possible to use any facilities that require code generation at runtime."
and
"No Dynamic Code Generation.
The System.Reflection.Emit is not available"
For example, this is a System.Text.Json limitation that actually cannot be used in Xamarin.Forms projects for iOS. More info here.
System.Text.Json Serializer does not appear to work on Xamarin iOS
I google a lot but not find any solution. Below is my problem :
I make a simple project where I use reference "IdentityServer4.Postgresql": "1.0.0"
where "using IdentityServer4.Services.InMemory" works perfectly.
But when I use "IdentityServer4.Postgresql": "2.0.0" then IdentityServer4.Services.InMemory always shows error.
That means version 2 of IdentityServer4.Postgresql not support IdentityServer4.Services.InMemory.
How can I use IdentityServer4.Services.InMemory for "IdentityServer4.Postgresql": "2.0.0"?
Thanks in advance.
IdentityServer4.Postgresql is not a part of the IdentityServer project, but sounds like a community contribution. You may have a better result by contacting the library creator.
Otherwise, you could try the official IdentityServer4.EntityFramework package that is maintained by the IdentityServer team in combination with an Entity Framework Core database provider for PostgreSQL.
The official quickstarts only show adding Entity Framework in the 8th quickstart. You'll have to do each one in succession up to the eighth one to fully understand / make sure to have the code you need.
After you have Entity Framework added to the configuration, you can support a Postgres database by just adding dependencies.
I have a Xamarin.Forms PCL project, and in it we are using JSON.NET to Serialize and deserialize. This works for 3 of our developers. On our 4th developers computer, anything that uses the deserialize function works fine, however if a line runs that uses Serialize, he gets the error:
System.MissingMethodException: Method 'Newtonsoft.Json.JsonConvert.SerializeObject' not found.
I'm having trouble figuring out how:
1) One method cant be found from a library, even though another one is working fine from the same library
2) How this is happening only on one developers machine?
We are using nuget to manage packages, and he has tried force reinstalling the latest version of json.net with no luck.
Does anyone have any idea what might fix this?
I need to upgrade an existing rather large application from Symfony 2.0.15 to Symfony 2.4.x (replace with current version).
I'm not quite sure what would be the best strategy to do so. Migration critical features like forms or esi are used, of course :)
Upgrade "step by step" from one major version to another (2.1, 2.2, 2.3, 2.4)
Upgrade directly from 2.0.x to 2.4
Do you have any tips / experience to share ? Would appreciate it :)
Thanks,
Stephan
Each new version comes with an update UPGRADE-2.x.md file containing all intructions to convert your application from the immediately previous version.
I had to do that on my project as well, and I found the step-by-step method more natural and easier to manage. Fact is, there is no file such file as UPGRADE-2.0-to-2.4.md that would help you out for a direct conversion to 2.4.
I shall first recommend to make sure that none of your code uses obsolete functionnalities of Symfony 2.0 (not sure if there are deprecated parts in this version, though), because these can be removed in ulterior versions and will not be included in the UPGRADE file.
If you have done indeep modifications of the core Symfony code, you may find that some undocumented modifications are needed. For instance, there is a custom error handler in my project, extending the Symfony error handler. Well, although it was not documented in the UPGRADE file, the signature of ErrorHandler::handle() was modified and needed to be updated in my custom handler.
Similarly, I had to modify some namespaces because files had been moved in the framework code.
The conversion is still ongoing and I'm currently experiencing a weird error I'm trying to get rid of: The 'request' scope on services registered on custom events generates errors in the logs.
I have an ASP.NET 4.0 web application that uses Entity Framework 4.3.1 and Self-Tracking Entities. It works fine until I add another ADO.NET Entity Data Model (.edmx) file to it. After that the project compiles without any errors, but as soon as it calls a self-tracking entity object, the application produces the System.InvalidOperationException: Mapping and metadata information could not be found for EntityType 'namespace.classname'.
I have tried adding the second ADO.NET Entity Data Model into a different namespace - but that does not help.
If I remove the added .edmx file from the project, the problem disappears.
If I remove the Self-tracking entity files (Model.tt and Model.Context.tt), the problem disappears.
It looks like Self-Tracking Entities cannot function properly when there is more than Entity Data Model.
Has anyone else experienced and solved this problem?
Make sure to use consistent Context generation throughout your solution.
Use the EF 5.x DbContext Generator on each of your Entity Data Models. You can either download the template via the ExtensionManager (search for EF 5.x) or here
I think self tracking entities are not supported from 4.1 (DbContext) onwards.
We had a few problems at work when upgrading from 4 to 4.2 with ste and we ended up reworking all to use DbContext and getting rid of ste. Since then it works like a charm!