Validate code with dependency diagrams

Why use dependency diagrams?

To make sure that code doesn't conflict with its design, validate your code with dependency diagrams in Visual Studio. This can help you:

• Find conflicts between dependencies in your code and dependencies on the dependency diagram.

• Find dependencies that might be affected by proposed changes.

  For example, you can edit the dependency diagram to show potential architecture changes and then validate the code to see the affected dependencies.

• Refactor or migrate code to a different design.

  Find code or dependencies that require work when you move the code to a different architecture.

Requirements

• Visual Studio

  To create a dependency diagram for a .NET Core project, you must have Visual Studio 2019 version 16.2 or later.

• A solution that has a modeling project with a dependency diagram. This dependency diagram must be linked to artifacts in C# or Visual Basic projects that you want to validate. See Create dependency diagrams from your code.

To see which editions of Visual Studio support this feature, see Edition support for architecture and modeling tools.

You can validate code manually from an open dependency diagram in Visual Studio or from a command prompt. You can also validate code automatically when running local builds or Azure Pipelines builds.

Live dependency validation

Dependency validation occurs in real time, and errors are shown immediately in the Error List.

• Live validation is supported for C# and Visual Basic.

• To enable full solution analysis when using live dependency validation, open the options settings from the gold bar that appears in the Error List.

  • You can permanently dismiss the gold bar if you are not interested in seeing all the architectural issues in your solution.
  • If you don't enable full solution analysis, the analysis is done only for the files being edited.

• When upgrading projects to enable live validation, a dialog shows the progress of the conversion.

• When updating a project for live dependency validation, the version of the NuGet package is upgraded to be the same for all projects, and is the highest version in use.

• Adding a new dependency validation project triggers a project update.

See if an item supports validation

You can link layers to websites, Office documents, plain text files, and files in projects that are shared across multiple apps, but the validation process won't include them. Validation errors won't appear for references to projects or assemblies that are linked to separate layers when no dependencies appear between those layers. Such references are not considered dependencies unless the code uses those references.

1. On the dependency diagram, select one or more layers, right-click your selection, and then click View Links.

2. In Layer Explorer, look at the Supports Validation column. If the value is false, the item does not support validation.

Include other .NET assemblies and projects for validation

When you drag items to the dependency diagram, references to the corresponding .NET assemblies or projects are added automatically to the Layer References folder in the modeling project. This folder contains references to the assemblies and projects that are analyzed during validation. You can include other .NET assemblies and projects for validation without manually dragging them to the dependency diagram.

1. In Solution Explorer, right-click the modeling project or the Layer References folder, and then click Add Reference.

2. In the Add Reference dialog box, select the assemblies or projects, and then click OK.

Validate code manually

If you have an open dependency diagram that is linked to solution items, you can run the Validate shortcut command from the diagram. You can also use the command prompt to run the msbuild command with the /p:ValidateArchitecture custom property set to True. For example, as you make changes in the code, perform layer validation regularly so that you can catch dependency conflicts early.

Validate code from an open dependency diagram

1. Right-click the diagram surface, and then click Validate Architecture.

   Note

   By default, the Build Action property on the dependency diagram (.layerdiagram) file is set to Validate so that the diagram is included in the validation process.

   The Error List window reports any errors that occur. For more information about validation errors, see Troubleshoot layer validation issues.

2. To view the source of each error, double-click the error in the Error List window.

   Note

   Visual Studio might show a code map instead of the source of the error. This occurs when either the code has a dependency on an assembly that is not specified by the dependency diagram, or the code is missing a dependency that is specified by the dependency diagram. Review the code map or the code to determine whether the dependency should exist. For more information about code maps, see Map dependencies across your solutions.

3. To manage errors, see Resolve layer validation errors.

Validate code at the command prompt

1. Open the Visual Studio command prompt.

2. Choose one of the following:

   • To validate code against a specific modeling project in the solution, run MSBuild with the following custom property.

     msbuild <FilePath+ModelProjectFileName>.modelproj /p:ValidateArchitecture=true
     

     -or-

     Browse to the folder that contains the modeling project (.modelproj) file and the dependency diagram and then run MSBuild with the following custom property:

     msbuild /p:ValidateArchitecture=true
     

   • To validate code against all modeling projects in the solution, run MSBuild with the following custom property:

     msbuild <FilePath+SolutionName>.sln /p:ValidateArchitecture=true
     

     -or-

     Browse to the solution folder, which must contain a modeling project that contains a dependency diagram, and then run MSBuild with the following custom property:

     msbuild /p:ValidateArchitecture=true
     

     Any errors that occur will be listed. For more information about MSBuild, see MSBuild and MSBuild Task.

   For more information about validation errors, see Troubleshoot layer validation issues.

Manage validation errors

During the development process, you might want to suppress some of the reported conflicts during validation. For example, you might want to suppress errors that you are already addressing or that are not relevant to your particular scenario. When you suppress an error, it is a good practice to log a work item in Team Foundation.

Create a work item for a validation error

• In the Error List window, right-click the error, point to Create Work Item, and then click the type of work item that you want to create.

Use these tasks to manage validation errors in the Error List window:

Validate code automatically

You can perform layer validation every time that you run a local build. If your team uses Azure DevOps, you can perform layer validation with gated check-ins, which you can specify by creating a custom MSBuild task, and use build reports to collect validation errors. To create gated check-in builds, see TFVC gated check-in.

To validate code automatically during a local build

Use a text editor to open the modeling project (.modelproj) file, and then include the following property:

<ValidateArchitecture>true</ValidateArchitecture>

- or -

1. In Solution Explorer, right-click the modeling project that contains the dependency diagram or diagrams, and then click Properties.

2. In the Properties window, set the modeling project's Validate Architecture property to True.

   This includes the modeling project in the validation process.

3. In Solution Explorer, click the dependency diagram (.layerdiagram) file that you want to use for validation.

4. In the Properties window, make sure that the diagram's Build Action property is set to Validate.

   This includes the dependency diagram in the validation process.

To manage errors in the Error List window, see Resolve layer validation errors.

Troubleshoot layer validation issues

The following table describes layer validation issues and their resolution. These issues differ from errors that result from conflicts between the code and the design. For more information about these errors, see Troubleshoot layer validation issues.

Resolve layer validation errors

When you validate code against a dependency diagram, validation errors occur when the code conflicts with the design. For example, the following conditions might cause validation errors to occur:

• An artifact is assigned to the wrong layer. In this case, move the artifact.

• An artifact, such as a class, uses another class in a way that conflicts with your architecture. In this case, refactor the code to remove the dependency.

To resolve these errors, update the code until no more errors appear during validation. You can perform this task in an iterative manner.

The following section describes the syntax that is used in these errors, explains the meaning of these errors, and suggests what you can do to resolve or manage them.

Related content

• Live dependency validation in Visual Studio
• Validate your system during development
• Video: Validate your architecture dependencies in real time