The task is not practical, it's just learning experiment.
I have .net5 app (which essentially is asp .net core app) which references onto neighboring project "WebControllers" which contains only Controller class.
WebControllers is .net5 class library into which I added reference to Microsoft.AspNetCore.Mvc.Core package. This package allows to create of working Controller object which is discovered by asp .net core infrastructure and which properly handles http requests.
Now I want inside my WebController objec create variable of ApplicationPartAttribute type. I tried doing this like that:
var aaa = new Microsoft.AspNetCore.Mvc.ApplicationParts.ApplicationPartAttribute("asd");
But Visual studio says to me that it don't know ApplicationPartAttribute class and it doesn't offer to use some namespace or add some package.
Let's go to the MSDN. MSDN about this type for .NET5 says:
Namespace: Microsoft.AspNetCore.Mvc.ApplicationParts
Assembly: Microsoft.AspNetCore.Mvc.Core.dll
Package: Microsoft.AspNetCore.App.Ref v5.0.0
Okay, let's try to install this package. Next errors are occured:
NU1213 The package Microsoft.AspNetCore.App.Ref 5.0.0 has a package
type DotnetPlatform that is incompatible with this project.
Package 'Microsoft.AspNetCore.App.Ref 5.0.0' has a package type
'DotnetPlatform' that is not supported by project 'WebControllers'
Why these errors are occured is unclear to me because both projects are .net5 projects and Microsoft.AspNetCore.App.Ref v5.0.0 is designed for .NET 5.
The question is: how can I use ApplicationPartAttribute in .net5 class library?
Add this code in your xxx.csproj file
<ItemGroup>
<FrameworkReference Include="Microsoft.AspNetCore.App"/>
</ItemGroup>
Related
I have a dotnet core library, a framework 4.7.2 library and a vb6 application.
I want to write a common library for them all to access and so choose .netstandard2.0
I tried a the 4.7.2 framework wrapper library between .netstandard2.0 library and vb6.
However I ran into assembly binding problems
Looking at the docs I see
In .NET Core, the process for exposing your .NET objects to COM has been significantly streamlined in comparison to .NET Framework.
However no mention .netstandard2.0
I decided to try following the docs anyway even though my project is using .netstandard2.0
I got up to the instructions on Generating the COM Host in which case the output files ProjectName.dll, ProjectName.deps.json, ProjectName.runtimeconfig.json and ProjectName.comhost.dll should build.
However the ProjectName.comhost.dll and ProjectName.runtimeconfig.json do not create.
I see in this dotnet standard issue that Microsoft plans on having tooling support in "Preview 4"
I am running VS 16.4.5
[Update]
I decided to try making a .net core wrapper library and enabling it for com.
I was able to add my .netstandard to the wrapper library via a nuget package (I build the .netstandard library using azure devops)
When I build my wrapper library the .dll, .deps.json, .pdb, .runtimeconfig.dev.json and .runtimeconfig.json files are created in a bin\Debug\netcoreapp3.1 folder.
However none of the .netstandard library files appear in the bin\debug folder.
I copied the .netstandard library and the .netcore wrapper libraries to the same folder and ran
regsvr32 MyCoreComWrapper.comhost.dll
However no .tlb file is created which I need to be able to use from VB6
I note the following in the docs
Unlike in .NET Framework, there is no support in .NET Core for
generating a COM Type Library (TLB) from a .NET Core assembly. The
guidance is to either manually write an IDL file or a C/C++ header for
the native declarations of the COM interfaces.
I found some information on github but would love a step by step guide to making the .tlb
I thought about using latebinding instead but am unsure of how to use it with a com library.
[Update]
I put a sample project on GitHub including some VB6 files.
With VB6 referencing the .tlb referenced with the framework library.
When I try to run that I get
Could not load file or assembly 'Microsoft.EntityFrameworkCore, Version=3.1.2.0,
Culture=neutral, PublicKeyToken=adb9793829ddae60' or one of its dependencies. The system cannot find the file specified.
So I copied all the files from my framework test project to my vb6 folder, rebuilt and ran.
Then I got the error
Could not load file or assembly 'Microsoft.Extensions.DependencyInjection.Abstractions, Version=3.1.0.0,
Culture=neutral, PublicKeyToken=adb9793829ddae60' or one of its dependencies. The system cannot find the file specified.
I see the file Microsoft.Extensions.DependencyInjection.dll is present with File version 3.100.220.6706
Regarding the .NET standard, I may be wrong but I think this is not applicable here because the COM interop stuff are at a higher level than the one .NET standard is targeting; we can only talk about either .NET Core or .NET Framework for COM interop.
If you want to generate a type library, you have few options.
By far, the easiest method is just to use .NET Framework. The fact that you are wanting to create a type library negates the advantages of .NET Core already because several COM, especially the "Automation" features are Windows-only. Using framework will be fine at least until .NET Core 5 comes out.
That said, if you have a business reason for using .NET Core but still need COM support, including the type library, then based on this GitHub comment, you should be able to compile your own IDL. Note that requires you to install C++ build tools because the MIDL compiler is not really a standalone thing that you can get without the rest of the C++ build tools.
It is strongly suggested to have had read the documentation on how .NET Core handles COM activation.
Assuming having the C++ build tools is not a barrier for you, the steps would be the following:
1) Create a .idl file that defines all your COM interfaces in the IDL format. That requires some translation between the .NET interface and the COM interface. Here's a partial example of how you'd need to translate between your C# interface and COM interface as defined in IDL:
[
Guid("<some gooey>"),
InterfaceType(ComInterfaceType.InterfaceIsDual)
]
public interface IFoo
{
string Bar { get; }
string Baz(int Fizz);
}
Would be translated into IDL:
[
uuid(<assembly gooey>),
version(1.0)
]
library myFoo
{
[
uuid(<some gooey>),
object,
dual
]
interface IFoo : IDispatch {
[propget] HRESULT Bar([out, retval] BSTR* retVal);
HRESULT Baz([in] long Fizz, [out, retval] BSTR* retVal);
}
}
Once you've defined the .idl file and it is an accurate representation, you can then use MIDL to compile the .idl file into a .tlb file. Usually something like midl foo.idl /tlb: foo.tlb. You should make use of the MIDL language reference to help you write the .idl file. As a quick way to get started, you could copy your C# interfaces to a .NET framework project, use tlbexp, then use oleview (available via Visual Studio Developer Command Prompt) or olewoo to view the resulting IDL file to get you started.
The next step is to then create registry keys so that your CLSID can reference the type library. You will need to have your assembly's GUID handy and it must be used as the library's uuid in the .idl file as well.
Using IFoo interface example, you would need to create the registry similar to below (using .reg format for easy sharing/comprehension and assuming per-user installation, rather than per-machine):
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Classes\Interface\{<some gooey>}]
#="IFoo"
[HKEY_CURRENT_USER\Software\Classes\Interface\{<some gooey>}\ProxyStubClsid32]
#="{00020424-0000-0000-C000-000000000046}"
[HKEY_CURRENT_USER\Software\Classes\Interface\{<some gooey>}\TypeLib]
#="{assembly gooey}"
"Version"="1.0"
You will also need to create the registry in the CLSID, Interface, TypeLib, and Record as needed. This article provides a good overview of all registry keys but keep in mind it's assuming .NET framework, not .NET Core, so not all keys are applicable, especially under the CLSID branch.
Note that when you run the regsvr32, it will normally create the keys in the CLSID and Interface branches but you will need to add the TypeLib keys under the Interface's branch and also an entry to the TypeLib branch. You also will need to create the ProgId keys, too if you want to support CreateObject functionality.
Initially, you can start with just a .reg file that you can manually update & maintain but if you have several objects, then it becomes desirable to automate this. This can be also managed via the DllRegisterServer call so that when you execute regsvr32, it will take care of registering the keys. On the other hand, you're now polluting your codebase with registration code. Some elect to use installers to do the registry keys write instead.
I hope that helps you get started!
The issue is due to assembly binding resolution that fails when ran from VB6 (IDE or compiled .exe file).
Here are the steps to solve it:
Compile the VB project, for example, let's assume the compiled file is Project1.exe.
Copy all .NET assemblies (including x86 and x64 directories, and languages directory if localized version is important) aside the compiled VB6 file
Now run Project1.exe, you will get an error like this:
The error is clearly a mismatch between the version of your assemblies aside the Project1.exe file and the version of referenced assemblies (not references you've created yourself but reference embedded in these assemblies... ). You don't see that when you start a .NET program because resolution is a very complex process that depends on a lot of parameters (and it's not getting any better with .NET Core, Framework, Standard, nugets, etc.).
To futher check it's a mismatch error, you can also use the Fuslogvw.exe (Assembly Binding Log Viewer) tool from the SDK.
Now we know it's an assembly version mismatch issue, what you can do is create a file named Project1.exe.config aside Project1.exe and add assembly binding redirects to it.
The easiest way to configure it is to redirect all possible versions to the ones present in the directory that contains your program, so in your case (and as of today, as all these can evolve...), it would be something like this, possibly for every assembly you reference directly or indirectly:
<configuration>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
...
<dependentAssembly>
<assemblyIdentity name="Microsoft.Extensions.DependencyInjection.Abstractions" publicKeyToken="adb9793829ddae60" />
<!-- 3.1.2.0 is the version of the assembly you ship -->
<bindingRedirect oldVersion="0.0.0.0-65535.65535.65535.65535" newVersion="3.1.2.0" />
</dependentAssembly>
...
</assemblyBinding>
</runtime>
</configuration>
Unfortunately, there are many satellite assemblies, and it's a bit tedious to create all redirects with correct information, so I've created a tool that creates a .config file with the redirects configured automatically for all .NET assemblies in a given directory: https://github.com/smourier/BindingRedirectGenerator.
If you want it to work for the VB6 IDE too, you'll have to use the same procedure in a VB6.exe.config file aside VB6.exe.
A reminder to myself
Use a demo UI to access the original DLL to confirm the call works. ( if you can't get it to work skip to making the App.Config for the unit test project using BindingRedirectGenerator )
Add a unit test in the com visible project to confirm the
call works.
Copy all the dlls created by both projects to the
release folder
For each com visible dll run as Administrator
c:\windows\microsoft.net\framework\v4.0.30319\regasm /verbose /codebase /tlb:MyLibrary.tlb c:\myproject\releasedlls\MyLibrary.dll
Install BindingRedirectGenerator to c:\brg say
At the command prompt change directory to c:\brg
BindingRedirectGenerator c:\myproject\releasedlls App.config
Rename App.config to MyVB6Project.exe.config and copy it to the same folder as MyVB6Project.exe
Remember to set up the files for the vb6.exe folder if you want to run it in the vb6 ide
Put the whole process in a script for future use ( I used a .bat)
Keep an eye on what nuget has put in app.config
Pay attention to the yellow warnings at build time!
I'm trying to add the Volo.Blogging module for ABP.io MVC project and I get the 'No DbContext was found in assembly 'ProjectName.Web'. Ensure that you're using the correct assembly and that the type is neither abstract nor generic.' error.
The bash commands:
abp new ProjectName
cd ProjectName
abp add-module Volo.Blogging -sp ./src/ProjectName.Web/ProjectName.Web.csproj
I'm on macOS Catalina, .NET Core 3.1.100, abp cli 1.1.2, Visual Studio 2019 for Mac.
Thank you.
Set the .DbMigrator project as the startup project instead:
abp add-module Volo.Blogging -sp ./src/ProjectName.DbMigrator/ProjectName.DbMigrator.csproj
References:
https://github.com/abpframework/abp/issues/2368
https://docs.abp.io/en/abp/latest/Getting-Started-AspNetCore-MVC-Template#using-the-dbmigrator-application
you must to check the library class for example avoid any name reserved in the .NET like as ( EF, Web ....)
Change the Library Class Name From EF
issue EF Library class
To Article.EF
Solution Fixed
I am getting System.IO.FileNotFoundException in my .Net Core Web API. So I've set up the below project to demonstrate the problem.
I created a.Net Standard library named DemoLibrary and added QRCoder dependency via NuGet.
Disclaimer: Reason for choosing the QRCoder is that the Web API doesn't use it by default. I don't use it in my project. In fact, I'm getting this exception for EntityFrameworkCore.
I created a new .Net Core Web API DemoWebAPI which has no other dependencies.
Then added the DemoLibrary to DemoWebAPI via Add Reference -> Browse -> DemoLibrary.dll.
This is my solution:
The DemoMethod method in Calculate class just creates the object of QRCodeGenerator.
public class Calculate
{
public static string DemoMethod()
{
QRCodeGenerator qrGenerator = new QRCodeGenerator();
return "";
}
}
And my ValuesController in DemoWebAPI just calls the method:
[HttpGet]
public ActionResult<IEnumerable<string>> Get()
{
return new string[] { "value1", "value2", DemoLibrary.Calculate.DemoMethod() };
}
Now, when I run the DemoWebAPI project I get below exception upon the call to the DemoMethod:
System.IO.FileNotFoundException: 'Could not load file or assembly 'QRCoder, Version=1.3.5.0, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.'
I understand the fact that I have to copy the QRCoder.dll file somewhere. But I fail to understand where to put it. I've already tried putting it in "bin/debug/netcoreapp2.2" of the DemoWebAPI and "bin/debug/netstandard2.0" of the DemoLibrary.
But I couldn't get it working.
Request: Please post your answer as descriptive as you can because I am new to .Net Core.
Edit:
I am aware of the NuGet servers. I have read topics like hosting a NuGet server in IIS and Azure. The reason behind DLL reference is I want to use my DLLs in two projects one of them is a .net core API and the other is .net framework class library which is compiled by NMAKE. I couldn't find any way to restore NuGet packages in the .MAK files.
It looks like you've merely added the DLL for DemoLibrary to your DemoWebApi project. That's not how you should be adding references. Since these are in the same solution, you should add a project reference. That will fix your issue.
Now, let me explain what's actually going on here. Your DemoLibrary has a dependency on QRCoder. It's a NuGet reference, which means that package will be restored (i.e. downloaded) and included in your DemoLibrary build output. However, it will be included as one or more DLLs along side your DemoLibrary.dll. When you then just reference DemoLibrary.dll, you're missing all these other DLLs that are part of DemoLibrary and thus, things don't work properly.
Now, when it comes to a project reference, things are little more complex. A project reference essentially wraps the referenced project into your other project. You can think of it as sort of a sub project. For all intents and purposes, it's like any dependency of the sub project becomes a dependency of the main project. That means that DemoWebAPI now technically has a NuGet package reference to QRCoder even though there's no explicit package reference in its project file. The dependency comes from your DemoLibary project. As such, with a project reference, all the necessary dependencies will be included, because it's as if the main project included those itself, by way of the sub project.
For what it's worth, you should virtually never include a DLL as a reference directly. That used to be required, but the concept of NuGet packages has all but eliminated the practice. Even if DemoLibrary was not in the same solution as DemoWebAPI (meaning you could no longer do a project reference), the correct way to use it would be to turn DemoLibary into a NuGet package, and then reference it in DemoWebAPI via a package reference, like any other NuGet package. You do not simply add the DLL.
I have a solution which contains an asp.net 5 app, a code library, and a test library. The libraries are also the new project.json style. I am not really sure how to refer to these libraries to distinguish them from the existing library project structure.
Anyway, all three projects were targeting dnx451/net451. I decided to try targeting dnx46/net46. The libraries build, but the asp.net dnx app fails. The error is:
The design time host build failed with the following error: Object reference not set to an instance of an object.
It is referencing the file Microsoft.DNX.targets at line 166.
There is another error that just says, "Object reference not set to an instance of the object." It says line 1, but doesn't reference a file.
To test I created a new solution with and empty asp.net 5 project and 2 class libraries. I changed dnx451 to dnx46, and net451 to net46, and it compiles fine. I am not sure what in my existing project is causing this error, or where to start looking.
By the way, dnx46/net46 are the only frameworks targeted. I have removed the core frameworks.
What a load of trial and error. Turns out the issue was the razor precompilation module as described here, http://davidzych.com/view-compilation-in-aspnet-5-with-the-razorprecompilemodule/.
You can read the github issue here, https://github.com/aspnet/dnx/issues/3003.
I first tried to comment out the precompilation class. However just that fact that the file was there, made dnx throw the error. I removed the precomilation file and now it compiles fine.
EDIT:
Alternatively you can add dnx451 back into your project, along with dnx46 and then the precomilation module will work fine.
In earlier .NET based applications I implemented a central method for returning application information, usually product name, version and legal copyright. This method was implemented via System.Reflection.Assembly or in newer applications via System.Diagnostics.FileVersionInfo. This allowed me keep the version number in a central place, namely the main assembly file, and edit it easily in Visual Studio project properties.
Now in DNX core all this doesn't seem to be available, neither System.Reflection nor System.Diagnostics.
How would you suggest to manage version information in a DNX core based ASP.NET 5 application in a platform neutral way?
You can implement something like dnx's IRuntimeEnvironment:
IRuntimeEnvironment
RuntimeEnvironment (the implementation of IRuntimeEnvironment)
Now in DNX core all this doesn't seem to be available, neither System.Reflection nor System.Diagnostics.
Not sure what you mean by that. System.Reflection and System.Diagnostics are available: https://github.com/aspnet/dnx/blob/219871c6063d00f8297eeafe93266f1048f59a45/src/Microsoft.Dnx.Host/project.json#L21-L23
If you cannot find a particular type, use the PackageSearch website to see in which NuGet package it is
The project.json file has a version number, name, description, copyright, authors etc. These are the same properties used to build a NuGet package. In fact, if you create a 'Class Library (Package)' project, you can compile it directly to a NuGet .nupkg file by checking the option in project properties.
I believe you can read this file using Configuration.GetConfigurationSection. ApplicationSettings is just a class with the properties from the project.json that you want to read.
var configurationSection = configuration.GetConfigurationSection(nameof(ApplicationSettings));
var applicationSettings = ConfigurationBinder.Bind<ApplicationSettings>(configurationSection);