JetBrains Rider 2021.3 Help

Code syntax style: file-scoped namespaces

Starting from C# 10, you can use file-scoped namespace declarations in files containing a single namespace.

If you prefer to stick to either file-scoped or block-scoped namespace declarations, JetBrains Rider lets you configure your preferences and maintain the consistency of your preferences throughout your codebase.

JetBrains Rider helps you enforce preferences for file-scoped namespaces in the existing code and takes your preferences into account when it produces new code with code completion and code generation features, applies code templates and performs refactorings.

Enforce preferences for file-scoped namespaces

JetBrains Rider can help you check single namespaces in your files for compliance with your preferences and if they do not comply, it highlights such declarations and suggests the corresponding quick-fix or fix in scope. Default JetBrains Rider's preferences say that file-scoped namespaces are preferred:

JetBrains Rider: 'To file-scoped namespace' quick-fix

However, you can configure your preferences in a different way, so that JetBrains Rider suggests making existing file-scoped namespaces block-scoped:

JetBrains Rider. 'To block-scoped namespace' quick-fix

Another option to enforce preferences for file-scoped namespaces in a bulk mode is code cleanup. You can either run code cleanup with one of the built-in profiles Full Cleanup or Reformat & Apply Syntax Style, or create and run a custom profile solely targeted at your specific task as described below.

Apply preferences for file-scoped namespaces with custom Code Cleanup profile

  1. Press Ctrl+Alt+S or choose File | Settings (Windows and Linux) or JetBrains Rider | Preferences (macOS) from the menu .

  2. Go to the cleanup profiles settings page: Editor | Code Cleanup.

  3. Create a new profile as described in the Create a new custom cleanup profile section. In the Selected profile settings section for the new profile, tick the Arrange namespaces (file-scoped vs. block-scoped checkbox. Optionally, you can enable other code cleanup tasks in this profile.

  4. Click Save in the Settings dialog to apply the modifications and let JetBrains Rider choose where to save them, or save the modifications to a specific settings layer using the Save To list. For more information, see layer-based settings.

  5. Select the scope where you want to enforce your preferences:

    • Set the caret anywhere in the file to enforce your preferences to the file.

    • Select one or more items in the Solution Explorer to enforce your preferences in the files under these nodes and their child items.

  6. Press Ctrl+E, C or choose Code | Reformat and Cleanup... from the main menu .

  7. In the Reformat and Cleanup Code dialog that opens, select the newly created profile and choose another scope if needed. .

  8. Click OK. JetBrains Rider will enforce your preferences in the selected scope.

If you want to enforce preferences for file-scoped namespaces without opening the Code Cleanup dialog to choose a profile, you can bind the created profile to the silent cleanup and run it by pressing Ctrl+E, F. You can also create a custom cleanup profile that would combine applying the preferences with other code style tasks.

You can enforce preferences for file-scoped namespaces in code that you have recently modified and are going to commit to Git. JetBrains Rider will run the selected cleanup profile before committing.

Clean up code before committing it to Git

  1. Press Ctrl+K or select Git | Commit from the main menu.

  2. In the Commit tool window, click Show Commit Options and in the Before Commit area, select the Cleanup with... checkbox.

  3. ClickChoose profile and choose your custom Code Cleanup profile.

  4. Click Commit or Commit and Push. JetBrains Rider will run code cleanup on the ranges staged for the commit, and then commit the changes.

You can enforce preferences for file-scoped namespaces every time you save changes in a file to make sure that your edits always comply with your code style. Note that this will only happen when you save changes explicitly with Ctrl+S or Ctrl+S and will not be triggered by auto-saving. However, all auto-saved files are placed to the 'reformat and cleanup' queue and will be processed on the next explicit save.

Automatically enforce preferences for file-scoped namespaces on saving changes

  1. Press Ctrl+Alt+S to open the IDE settings and select Tools | Actions on Save.

  2. Select Reformat and Cleanup Code, choose your custom Code Cleanup profile and whether to apply it to the whole file or only to the changed lines.

  3. The next time you finish editing and save the file or all files , JetBrains Rider will clean up the affected files using the selected profile.

Configure preferences for file-scoped namespaces

Your namespace declaration style preferences are saved using the mechanism of layer-based settings. Among other things, this mechanism allows you to maintain different preferences for different solutions as well as to keep these preferences under a VCS and automatically share them with your team members.

Configure namespace declaration style in settings

  1. Go to the Editor | Code Style | C# page of JetBrains Rider settings Ctrl+Alt+S, and then select the Syntax Style tab .

  2. Find the Namespaces option under Code body and choose File-scoped or Block-scoped.

  3. The selectors in the right column allow you to set severity levels of code inspections detecting code that differs from your preferences.

  4. Click Save in the Settings dialog to apply the modifications and let JetBrains Rider choose where to save them, or save the modifications to a specific settings layer using the Save To list. For more information, see layer-based settings.

You can also change your preferences for namespace declarations right in the editor, where a corresponding issue is highlighted:

Change preference for namespace declaration style from the editor

  1. Set the caret to a code issue highlighted by a JetBrains Rider's inspection.

  2. Press Alt+Enter or click the action indicator to the left of the caret to open the action list.

  3. In the action list, choose Inspection "Use preferred namespace body style..." | Configure code style and then select a desired preference:

    JetBrains Rider: Changing code style preference for namespace body
  4. Your change will be saved using the smart save logic.

  5. If you need to save the modified style preference in a shared settings layer, click the Configure code style menu item or press Enter when it is selected. JetBrains Rider will open the Editor | Code Style | C# | Syntax Style page of JetBrains Rider settings where you can modify your preference as needed, click Save To and then choose the desired settings layer.

Last modified: 18 November 2021