Create dependency diagrams from your code

Applies to: Visual Studio Visual Studio for Mac

To visualize your software system's high-level, logical architecture, create a dependency diagram in Visual Studio. To make sure that your code stays consistent with this design, validate your code with a dependency diagram. You can create dependency diagrams for Visual C# and Visual Basic projects. To see which editions of Visual Studio support this feature, see Edition support for architecture and modeling tools.

A dependency diagram lets you organize Visual Studio solution items into logical, abstract groups called layers. You can use layers to describe major tasks that these artifacts perform or the system's major components.

Each layer might contain other layers that describe more detailed tasks. You can also specify the intended or existing dependencies between layers. These dependencies, represented as arrows, show the layers that use or can use the functionality represented by other layers. To maintain architectural control of the code, show the intended dependencies on the diagram and then validate the code against the diagram.

Video: Validate your architecture dependencies in real time

Create a dependency diagram

Before you create a dependency diagram, ensure that your solution has a modeling project.

Add a new dependency diagram to a modeling project

1. On the Architecture menu, choose New Dependency Diagram.

2. Under Templates, choose dependency diagram.

3. Name the diagram.

4. In Add to Modeling Project, browse to and select an existing modeling project in your solution.

   -or-

   Choose Create a new modeling project to add a new modeling project to the solution.

   Note

   The dependency diagram must exist inside a modeling project. However, you can link it to items anywhere in the solution.

5. Make sure to save both, the modeling project and the dependency diagram.

Drag and drop, or copy and paste, from a Code Map

1. Generate a Code Map for the solution using the Architecture menu.

2. Consider applying a Code Map filter to remove solution folders and "Test Assets" if you only want to enforce dependencies in product code.

3. On the generated Code Map, remove the "External" node, or expand it to show external assemblies, depending on whether you want to enforce namespace dependencies. Delete non-required assemblies from the Code Map.

4. Create a new Dependency Diagram for the solution using the Architecture menu.

5. Select all the nodes on the Code Map (use Ctrl + A, or use the rubber band selection by pressing the Shift key before you click, drag, and release.

6. Drag and drop, or copy and paste, the selected elements to the new Dependency Validation diagram.

7. This shows the current app architecture. Decide what you want the architecture to be and modify the dependency diagram accordingly.

Create layers from artifacts

You can create layers from Visual Studio solution items, such as projects, code files, namespaces, classes, and methods. This automatically creates links between layers and items, including them in the layer validation process.

You can link layers to items that don't support validation, such as Word documents or PowerPoint presentations. This lets you associate a layer with specifications or plans. You can also link layers to files in projects that are shared across multiple apps, but the validation process won't include those layers, which appear with generic names such as "Layer 1" and "Layer 2".

To see if a linked item supports validation, open Layer Explorer and examine the Supports Validation property of the item. See Managing links to artifacts.

The number on a layer indicates the number of artifacts that are linked to the layer. However, when reading this number, remember:

• If a layer links to an artifact that contains other artifacts, but the layer doesn't link directly to the other artifacts, then the number includes only the linked artifact. However, the other artifacts are included for analysis during layer validation.

  For example, if a layer is linked to a single namespace, then the number of linked artifacts is 1, even if the namespace contains classes. If the layer also has links to each class in the namespace, then the number will include the linked classes.

• If a layer contains other layers that are linked to artifacts, then the container layer is also linked to those artifacts, even though the number on the container layer doesn't include those artifacts.

Manage links between layers and artifacts

1. On the dependency diagram, open the shortcut menu for the layer, and then choose View Links.

   Layer Explorer shows the artifact links for the selected layer.

2. Use the following tasks to manage these links:

Reverse-engineer existing dependencies

A dependency exists wherever an artifact that is associated with one layer has a reference to an artifact that is associated with another layer. For example, a class in one layer declares a variable that has a class in another layer. You can reverse-engineer existing dependencies for artifacts that are linked to layers on the diagram.

• Select one or multiple layers, open the shortcut menu for a selected layer, and then choose Generate Dependencies.

  If you see some dependencies that shouldn't exist, you can edit these dependencies to align them with the intended design.

Edit layers and dependencies to show the intended design

To describe the changes that you plan to make to your system or the intended architecture, edit the dependency diagram:

Change how elements appear on the diagram

You can change the size, shape, color, and position of layers or the color of dependencies by editing their properties.

Discover patterns and dependencies on a code map

While creating dependency diagrams, you might also create code maps. These diagrams can help you discover patterns and dependencies while you explore the code. Use Solution Explorer, Class View, or Object Browser to explore assemblies, namespaces, and classes - which often correspond well to existing layers. For more information about code maps, see:

• Map dependencies across your solutions

• Use code maps to debug your applications

• Find potential problems using code map analyzers

See also

• Edition support for architecture and modeling tools
• Video: Validate your architecture dependencies in real time
• Dependency Diagrams: Reference
• Dependency Diagrams: Guidelines
• Validate code with dependency diagrams
• Visualize code