Sist endret: 3. mar. 2023

Breaking changes

Oversikt over breaking changes introdusert i App Nuget-pakker i v7.0.0.

If your application still is on version v5 or lower you should read the breaking changes guides until your application is updated to v6.

Updating Altinn.App.* PackageReferences from v6 to v7

As mentioned here we have moved the code around and reduced the number of nugets to two.

To upgrade from v6 nuget to v7 nugets the Altinn.App.* PackageReferences in App/App.csproj needs to be changed from:

  <ItemGroup>
    <PackageReference Include="Altinn.App.Api" Version="6.0.2">
      <CopyToOutputDirectory>lib\$(TargetFramework)\*.xml</CopyToOutputDirectory>
    </PackageReference>
    <PackageReference Include="Altinn.App.Common" Version="6.0.2" />
    <PackageReference Include="Altinn.App.PlatformServices" Version="6.0.2" />
    <!-- Additional PackageReferences -->
  </ItemGroup>

to

  <ItemGroup>
    <PackageReference Include="Altinn.App.Api" Version="7.0.0">
      <CopyToOutputDirectory>lib\$(TargetFramework)\*.xml</CopyToOutputDirectory>
    </PackageReference>
    <PackageReference Include="Altinn.App.Core" Version="7.0.0" />
  <!-- Additional PackageReferences -->
  </ItemGroup>

Once you or your IDE has completed the dotnet restore process your code will have multiple compilation warnings. Work your way through the rest of this page and you will remove them one at a time.

Upgrading Program.cs

It’s highly recommended to follow the migration guide to v6 if your application still hasn’t been upgraded to v6 from v4 or v5.

In previous versions Altinn provided code and registration of custom/override services which were hard to separate. As an attempt to make it easier to see customer provided services, we have extracted most of our code and introduced a new method at the top of Program.cs

Steps:

  1. Identify the custom services your application has registered in Program.cs. Take a note of these as we will have to register them again later.
  2. Copy and paste the version 7 of Program.cs from our template at altinn/app-template-dotnet into your App/Program.cs (replacing existing code)
  3. Register your apps custom services from step 1 in the method RegisterCustomAppServices

Replacing or upgrading old classes to implement new Interfaces

Upgrade and register DataProcessingHandler

Custom logic while performing DataWrite or DataRead are from v7 handled by registering a service class implementing Altinn.App.Core.Features.DataProcessing.IDataProcessor

If your App/logic/DataProcessing/DataProcessingHandler.cs is similar to the following code, you can delete the file and move on Replace InstantiationHandler.cs and register new service.

using System;
using System.Threading.Tasks;
using Altinn.Platform.Storage.Interface.Models;

namespace Altinn.App.AppLogic.DataProcessing
{
    public class DataProcessingHandler
    {
        public async Task<bool> ProcessDataRead(Instance instance, Guid? dataId, object data)
        {
            return await Task.FromResult(false);
        }

        public async Task<bool> ProcessDataWrite(Instance instance, Guid? dataId, object data)
        {
            return await Task.FromResult(false);
        }
    }
}

If you have custom code in this class complete the steps below:

  1. Create a new class named DataProcessor in the folder App/logic/DataProcessing, make the class implement the interface Altinn.App.Core.Features.IDataProcessor. The file should now look something like this:
    using System;
     using System.Threading.Tasks;
     using Altinn.App.Core.Features;
     using Altinn.Platform.Storage.Interface.Models;
    
     namespace Altinn.App.AppLogic.DataProcessing;
    
     public class DataProcessor : IDataProcessor
     {
         public async Task<bool> ProcessDataRead(Instance instance, Guid? dataId, object data)
         {
         }
    
         public async Task<bool> ProcessDataWrite(Instance instance, Guid? dataId, object data)
         {
         }
     }
    
    Note that you might have to add the async keyword if they aren’t added by default. You only need to add them if you do async calls within your code.
  2. Move your code from the file App/logic/DataProcessing/DataProcessingHandler.cs to the file you just created.
  3. Register DataProcessor in the method RegisterCustomAppServices App/Program.cs
     void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
    {
      services.AddTransient<IDataProcessor, DataProcessor>();
    
      // Other custom services
    }
    
    Remember to add the necessary usings. (In VSC you should be able to use Ctrl + . (windows-version with C# plugin installed) to get using-suggestions)
  4. Delete the old DataProcessingHandler.cs file

Replace InstantiationHandler.cs and register new service

The logic that previously was defined in App/logic/InstantiationHandler.cs is now defined by implementing two interfaces

  • IInstantiationProcessor is used to do custom data/instance manipulation during instantiation. Replaces the method DataCreation in InstantiationHandler
  • IInstantiationValidator is used to do custom validation during Instantiation. Replaces the method RunInstantiationValidation in InstantiationHandler

If your App/logic/InstantiationHandler.cs looks like the code below, you have no custom code here and can delete the class now and move on to Upgrade ValidationHandler.cs and register new service

using System.Collections.Generic;
using System.Threading.Tasks;
using Altinn.App.Services.Interface;
using Altinn.App.Services.Models.Validation;
using Altinn.Platform.Storage.Interface.Models;

namespace Altinn.App.AppLogic
{
    public class InstantiationHandler
    {
        private IProfile _profileService;
        private IRegister _registerService;

        public InstantiationHandler(IProfile profileService, IRegister registerService)
        {
            _profileService = profileService;
            _registerService = registerService;
        }

        public async Task<InstantiationValidationResult> RunInstantiationValidation(Instance instance)
        {
            return await Task.FromResult((InstantiationValidationResult)null);
        }

        public async Task DataCreation(Instance instance, object data, Dictionary<string, string> prefill)
        {
            await Task.CompletedTask;
        }
    }
}

If you have custom code in the method DataCreation complete these steps:

  1. Create a new Class named InstantiationProcessor.cs in App/logic/DataProcessing and implement the interface Altinn.App.Core.Features.IInstantiationProcessor. The class can be named or placed where you like, this is only a suggestion. The file should look something like this now:
    using System.Collections.Generic;
    using System.Threading.Tasks;
    using Altinn.App.Core.Features;
    using Altinn.Platform.Storage.Interface.Models;
    
    namespace Altinn.App.AppLogic.DataProcessing;
    
    public class InstantiationProcessor : IInstantiationProcessor
    {
        public async Task DataCreation(Instance instance, object data, Dictionary<string, string> prefill)
        {
    
        }
    }
    
    Note that you might have to add the async keyword if they aren’t added by default. You only need to add them if you do async calls within your code.
  2. Move all the code from DataCreation in ÌnstantiationHandler.cs into the method DataCreation in the class you just created.
  3. Register InstantiationProcessor in the method RegisterCustomAppServices App/Program.cs
     void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
    {
      services.AddTransient<IInstantiationProcessor, InstantiationProcessor>();
    
      // Other custom services
    }
    
    Remember to add the necessary usings.

If you have custom code in the method RunInstantiationValidation complete the steps below, if not delete App/logic/InstantiationHandler.cs and move on to Upgrade ValidationHandler.cs and register new service:

  1. Create a new Class named InstantiationValidator.cs in App/logic/Validation and implement the interface Altinn.App.Core.Features.IInstantiationValidator. The class can be named or placed where you like, this is only a suggestion. The file should look something like this now:
    using System.Threading.Tasks;
    using Altinn.App.Core.Features;
    using Altinn.App.Core.Models.Validation;
    using Altinn.Platform.Storage.Interface.Models;
    
    namespace Altinn.App.AppLogic.Validation;
    
    public class InstantiationValidator : IInstantiationValidator
    {
        public async Task<InstantiationValidationResult> Validate(Instance instance)
        {
    
        }
    }
    
  2. Move all the code from RunInstantiationValidation in ÌnstantiationHandler.cs into the method Validate in the class you just created.
  3. Register InstantiationValidator in the method RegisterCustomAppServices App/Program.cs
     void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
    {
      services.AddTransient<IInstantiationValidator, InstantiationValidator>();
    
      // Other custom services
    }
    
    Remember to add the necessary usings.

You can now delete the file App/logic/InstantiationHandler.cs

Upgrade ValidationHandler.cs and register new service

Custom data and task validation is in v7 handled by registering a service class implementing Altinn.App.Core.Features.IInstanceValidator.

If your App/logic/Validation/ValidationHandler.cs looks like the code below, you have no custom code and can delete the file and move on to Upgrading custom PdfFormatting.

using System.Threading.Tasks;
using Altinn.Platform.Storage.Interface.Models;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.ModelBinding;

namespace Altinn.App.AppLogic.Validation
{
    public class ValidationHandler
    {
        private IHttpContextAccessor _httpContextAccessor;

        public ValidationHandler(IHttpContextAccessor httpContextAccessor = null)
        {
            _httpContextAccessor = httpContextAccessor;
        }

        public async Task ValidateData(object data, ModelStateDictionary validationResults)
        {
            await Task.CompletedTask;
        }

        public async Task ValidateTask(Instance instance, string taskId, ModelStateDictionary validationResults)
        {
            await Task.CompletedTask;
        }
    }
}

If you have custom code here complete the steps below:

  1. Create a new class named InstanceValidator in the folder App/logic/Validation, make the class implement the interface Altinn.App.Core.Features.IInstanceValidator. The file should now look something like this:
    using System.Threading.Tasks;
    using Altinn.App.Core.Features;
    using Altinn.Platform.Storage.Interface.Models;
    using Microsoft.AspNetCore.Mvc.ModelBinding;
    
    namespace Altinn.App.AppLogic.Validation;
    
    public class InstanceValidator : IInstanceValidator
    {
        public async Task ValidateData(object data, ModelStateDictionary validationResults)
        {
        }
    
        public async Task ValidateTask(Instance instance, string taskId, ModelStateDictionary validationResults)
        {
        }
    }
    
  2. Move the code in ValidateData method in the old class ValidatorHandler to the new one in InstanceValidator class.
  3. Move the code in ValidateTask method in the old class ValidatorHandler to the new one in InstanceValidator class.
  4. Register InstanceValidator in the method RegisterCustomAppServices App/Program.cs
    void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
    {
      services.AddTransient<IInstanceValidator, InstanceValidator>();
    
      // Other custom services
    }
    
    Remember to add the necessary usings.
  5. Delete the ValidationHandler.cs file.

Upgrading Custom PDF formatting logic

In previous versions dynamic customization was handled by registering a service implementing ICustomPdfHandler. In v7 this is done by registering a service implementing Altinn.App.Core.Features.Pdf.IPdfFormatter.

If your App/logic/Pdf/PdfHandler.cs looks like the following code, you have no custom code and can delete the file and move on to Updating PageOrder logic

using System.Threading.Tasks;
using Altinn.App.Common.Models;
using Altinn.App.PlatformServices.Interface;

namespace Altinn.App.AppLogic.Print
{
    public class PdfHandler: ICustomPdfHandler
    {
        public async Task<LayoutSettings> FormatPdf(LayoutSettings layoutSettings, object data)
        {
            return await Task.FromResult(layoutSettings);
        }
    }   
}

If not, complete the steps below:

  1. Create a new class named PdfFormatter in the folder App/logic/Pdf. Make the class implement the interface Altinn.App.Core.Features.IPdfFormatter. The file should new look something like this:
    using System.Threading.Tasks;
    using Altinn.App.Core.Features;
    using Altinn.App.Core.Models;
    
    namespace Altinn.App.AppLogic.Print
    {
        public class PdfHandler: IPdfFormatter
        {
            public async Task<LayoutSettings> FormatPdf(LayoutSettings layoutSettings, object data)
            {
            }
        }   
    }
    
  2. Move youre code from ICustomPdfHandler to the newly created PdfFormatter class.
  3. Register PdfFormatter in the method RegisterCustomAppServices App/Program.cs
     void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
    {
      services.AddTransient<IPdfFormatter, PdfFormatter>();
    
      // Other custom services
    }
    
    Remember to add the necessary usings.
  4. Delete the old file
  5. Remove the transient service registration of the old class from Program.cs. Should look something like this: services.AddTransient<ICustomPdfHandler, PdfHandler>(); (remove it by deleteing the line)

Upgrading PageOrder.cs

In v5 of the nugets tracks or pageorder was extracted in a non-breaking way from App.cs. The old way was deprecated in v6 and now removed in v7.

The new way of defining page order in v5 has not really changed in v7, but some interfaces have been moved to a different namespace.

If you don’t have any classes implementing IPageOrder, you can safely move on to Moving code form App.cs and removing it

If you do have a class implementing IPageOrder here are some changes in namespace that might be helpful to know:

  • The namespace for IPageOrder has changed from Altinn.App.Services.Interfaces to Altinn.App.Core.Features.PageOrder
  • The namespace for AppIdentifier has changed from Altinn.App.PlatformSerices.Models to Altinn.App.Core.Models
  • The namespace for IAppResources has changed from Altinn.App.PlatformSerices.Interface Altinn.App.Core.Interface

Moving eFormidling code

This next chapter only applies to applications which integrates with eFormidling. If yours don’t you can move on to Moving code from App.cs and removing it

To determine if your app is integrated against eFormidling, check if you have defined the method GenerateEFormidlingMetadata defined in App/logic/App.cs

Move code from GenerateEFormidlingMetadata in App.cs

  1. Create a new class named EFormidlingMetadata in the folder App/logic/EFormidling. You can name and place the file whatever and wherever you like, this is just a suggestion. Make the newly created class implement the interface Altinn.App.Core.EFormidling.Interface.IEFormidlingMetadata. The file should look something like this now:
    using System.IO;
    using System.Threading.Tasks;
    using Altinn.App.Core.EFormidling.Interface;
    using Altinn.Platform.Storage.Interface.Models;
    
    namespace Altinn.App.logic.EFormidling;
    
    public class EFormidlingMetadata : IEFormidlingMetadata
    {
        public Task<(string MetadataFilename, Stream Metadata)> GenerateEFormidlingMetadata(Instance instance)
        {
    
        }
    }
    
  2. Move the code from the method GenerateEFormidlingMetadata in App/logic/App.cs to the method GenerateEFormidlingMetadata in the class you just created.

Move code from GetEFormidlingReceivers in App.cs

If you have no definition of GetEFormidlingReceivers in App/logic/App.cs, you can move on to Register Eformidling implementation. If it is defined complete the following steps:

  1. Create a new class named EFormidlingReceiversin App/logic/EFormidling. You can name and place the file whatever and wherever you like, this is just a suggestion. Make the new class implement the interface Altinn.App.Core.EFormidling.Interface.IEFormidlingReceivers. The file should look something like this now:
    using System.Collections.Generic;
    using System.Threading.Tasks;
    using Altinn.App.Core.EFormidling.Interface;
    using Altinn.Common.EFormidlingClient.Models.SBD;
    using Altinn.Platform.Storage.Interface.Models;
    
    namespace Altinn.App.logic.EFormidling;
    
    public class EFormidlingReceivers : IEFormidlingReceivers
    {
        public Task<List<Receiver>> GetEFormidlingReceivers(Instance instance)
        {
        }
    }
    
  2. Move the code from the method GetEFormidlingReceivers in App/logic/App.cs to the method GetEformidlingReceivers in the class you just created.

Register Eformidling implementation

This step depends on the previous steps. Whether your code has custom logic for GetEFormidlingReceivers or not.

In the method RegisterCustomAppServices in Program.cs you need to register the eFormidling implementation.

To add eFormidling services and your implementation EFormidlingMetadata add this to your RegisterCustomAppServices.

void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
{
    services.AddEFormidlingServices<EFormidlingMetadata>(config);
}

This will register the default implementation of IEFormidlingReceivers

If you have a custom implementation of IEFormidlingReceivers you should add your implementation as the second type parameter:

void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
{
    services.AddEFormidlingServices<EFormidlingMetadata, EFormidlingReceivers>(config);
}

Moving code from App.cs and removing it

As we are going to extract code from App.cs and eventually remove it, there is no need to pay attention to compilation error.

The next sections will extract custom code from App.cs, if any, and move it to its new home.

Moving custom code in RunProcessDataRead and RunProcessDataWrite

If RunProcessDataRead and RunProcessDataWrite in App/App.cs looks like the code below, you have no custom code and can safely move on to Moving custom code in RunDataValidation and RunTaskValidation. If not, complete the steps below:

        public override async Task<bool> RunProcessDataRead(Instance instance, Guid? dataId, object data)
        {
            return await _dataProcessingHandler.ProcessDataRead(instance, dataId, data);
        }

        public override async Task<bool> RunProcessDataWrite(Instance instance, Guid? dataId, object data)
        {
            return await _dataProcessingHandler.ProcessDataWrite(instance, dataId, data);
        }
  1. Move custom code in RunProcessDataRead to the method ProcessDataRead in App/logic/DataProcessing/DataProcessor.cs that was created and registered in the step Upgrade and register DataProcessingHadler
  2. Move custom code in RunProcessDataWrite to the method ProcessDataWrite in App/logic/DataProcessing/DataProcessor.cs

Moving custom code in RunDataValidation and RunTaskValidation

If RunDataValidationand RunTaskValidation looks like the code below, you have no custom code and can safely move on to Moving custom code in RunInstantiationValidation and RunDataCreation. If not, complete the steps below:

public override async Task RunDataValidation(object data, ModelStateDictionary validationResults)
{
    await _validationHandler.ValidateData(data, validationResults);
}

public override async Task RunTaskValidation(Instance instance, string taskId, ModelStateDictionary validationResults)
{
    await _validationHandler.ValidateTask(instance, taskId, validationResults);
}
  1. Move custom code in RunDataValidation to the method ValidateData in App/logic/Validation/InstanceValidator.cs that you created and registered here Upgrade ValidationHandler.cs and register new service.
  2. Move custom code in RunTaskValidation to the method ValidateTask in App/logic/Validation/InstanceValidator.cs

Moving custom code in RunDataCreation

If RunDataCreation looks like the code below you have no custom code and can safely move on to Moving custom code in RunInstantiationValidation. If not, complete the steps below:

public override async Task RunDataCreation(Instance instance, object data, Dictionary<string, string> prefill)
{
    await _instantiationHandler.DataCreation(instance, data, prefill);
}
  1. If you haven’t already: Create a new class named InstantiationProcessor.cs in App/logic/DataProcessing and implement the interface Altinn.App.Core.Features.IInstantiationProcessor. The class can be named or placed where you like, this is only a suggestion. The file should look something like this now:
    using System.Collections.Generic;
    using System.Threading.Tasks;
    using Altinn.App.Core.Features;
    using Altinn.Platform.Storage.Interface.Models;
    
    namespace Altinn.App.AppLogic.DataProcessing;
    
    public class InstantiationProcessor : IInstantiationProcessor
    {
        public async Task DataCreation(Instance instance, object data, Dictionary<string, string> prefill)
        {
    
        }
    }
    
  2. Move custom code in DataCreation to the method DataCreation in App/logic/DataProcessing/InstantiationHandler.cs that you created and registered here Replace InstantiationHandler.cs and register new service
  3. Register InstantiationProcessor in the method RegisterCustomAppServices App/Program.cs
    void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
    {
      services.AddTransient<IInstantiationProcessor, InstantiationProcessor>();
    
      // Other custom services
    }
    
    Remember to add the necessary usings.

Moving custom code in RunInstantiationValidation

If RunInstantiationValidation looks like the code below, you have no custom code and can safely move on to Moving custom code in RunProcessTaskEnd. If not, complete the steps below:

public override async Task<InstantiationValidationResult> RunInstantiationValidation(Instance instance)
{
    return await _instantiationHandler.RunInstantiationValidation(instance);
}
  1. If you haven’t already: Create a new Class named InstantiationValidator.cs in App/logic/Validation and implement the interface Altinn.App.Core.Features.IInstantiationValidator. The class can be named or placed wherever you like, this is only a suggestion. The file should look something like this now:
    using System.Threading.Tasks;
    using Altinn.App.Core.Features;
    using Altinn.App.Core.Models.Validation;
    using Altinn.Platform.Storage.Interface.Models;
    
    namespace Altinn.App.AppLogic.Validation;
    
    public class InstantiationValidator : IInstantiationValidator
    {
        public async Task<InstantiationValidationResult> Validate(Instance instance)
        {
    
        }
    }
    
  2. Move all the code from RunInstantiationValidation in ÌnstantiationHandler.cs into the method Validate in the class you just created.
  3. Register InstantiationValidator in the method RegisterCustomAppServices App/Program.cs
     void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
    {
      services.AddTransient<IInstantiationValidator, InstantiationValidator>();
    
      // Other custom services
    }
    
    Remember to add the necessary usings.

Moving custom code in RunProcessTaskEnd

If RunProcessTaskEnd looks like the code below, you have no custom code and can safely move on to Moving custom code in GetPageOrder. If not, complete the steps below:

public override async Task RunProcessTaskEnd(string taskId, Instance instance)
{
    await Task.CompletedTask;
}
  1. Create a new class implementing the Interface Altinn.App.Core.Features.IProcessTaskEnd. You can name and place this class wherever you like, but as a suggestion you can create and place it in the folder App/logic/TaskProcessors and name the file TaskProcessor. The class should look something like this after the interface is implemented:
    using System.Threading.Tasks;
    using Altinn.App.Core.Features;
    using Altinn.Platform.Storage.Interface.Models;
    
    namespace Altinn.App.AppLogic.TaskProcessors;
    
    public class ProcessTaskEnd: IProcessTaskEnd
    {
        public Task End(string taskId, Instance instance)
        {
            return Task.CompletedTask;
        }
    }
    
  2. Move code from RunProcessTaskEnd to the method End in the class implementing IProcessTaskEnd
  3. Register your custom implementation of IProcessTaskEnd in the method RegisterCustomAppServices inside App/Program.cs
      void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
     {
       services.AddTransient<IProcessTaskEnd, ProcessTaskEnd>();
    
       // Other custom services
     }
    
    Remember to add the necessary usings.

Moving custom code in GetPageOrder

If GetPageOrder in App/logic/App.cs is not present, you have no custom code and can safely move on the Removing App.cs. If not, complete the steps below:

  1. Create a new class implementing the interface Altinn.App.Core.Features.IPageOrder. You can name and place this class wherever you like in your project, but a suggestion is to name it PageOrder and place it in the folder App/logic/PageOrder. The file should look something like this now:
    using System.Collections.Generic;
    using System.Threading.Tasks;
    using Altinn.App.Models;
    using Altinn.App.Core.Features;
    using Altinn.App.Core.Interface;
    using Altinn.App.Core.Models;
    
    namespace Altinn.App.AppLogic.PageOrder;
    
    public class PageOrder : IPageOrder
    {
        public async Task<List<string>> GetPageOrder(AppIdentifier appIdentifier, InstanceIdentifier instanceIdentifier, string layoutSetId, string currentPage, string dataTypeId, object formData)
        {
        }
    }
    
  2. Move the code from GetPageOrder to the mehod GetPageOrder in the class you just created.
  3. Register your custom implementation of IPageOrder in the mehtod RegisterCustomAppServices inside App/Program.cs
      void RegisterCustomAppServices(IServiceCollection services, IConfiguration config)
     {
       services.AddTransient<IPageOrder, PageOrder>();
    
       // Other custom services
     }
    
    Remember to add the necessary usings.

Removing App.cs

Now all your custom code should be moved out of App.cs. Take a look in the file and check if there is any code left that you need to move.

See the old default App.cs here

If you don’t see any code worth keeping, go ahead and delete the file App.cs. All the logic Altinn used to have in this file, is moved elsewhere in our code and should not leak into your application code.

Noteable namespace changes

This is truly not a complete list of alle the changes to namespace we have done in v7, for that see the actual PR on Github

The following list is some of the namespaces that have changed that we think will affect most of the applications:

  • Interfaces that service owners naturally overrides/customize is moved from Altinn.App.PlatformServices.Interfaces to Altinn.App.Core.Features
  • Altinn.App.Common.Models namespace is moved to Altinn.App.Core.Models
  • Altinn.App.PlatformServices.Interface.ICustomPdfHandler interface is moved and renamed to: Altinn.App.Core.Features.Pdf.IPdfFormatter

Recomended plugin for Visual Studio Code

There are a lot of changes to namespaces so we strongly recommend using Visual Studio Code with the C# plugin installed. This will give you code help for importing and locating new or changed interfaces.

Plugin information:
Name: C#
Id: ms-dotnettools.csharp
Description: C# for Visual Studio Code (powered by OmniSharp).
Publisher: Microsoft
VS Marketplace Link: https://marketplace.visualstudio.com/items?itemName=ms-dotnettools.csharp