JetBrains Rider 2023.3 Help

Make fields readonly

It is often reasonable to use the 'readonly' modifier for fields that are assigned in the declaration or in a constructor and only have read usages. By default, JetBrains Rider suggests that you make a field readonly if the above conditions are met. It highlights such fields and suggests the corresponding quick-fix or fix in scope:

Make field readonly quick-fix

If you do not want JetBrains Rider to suggest this, you can disable the code inspection that detects it (Field can be made readonly).

The reverse functionality is also available. If you decide to change a readonly field later in your code (which leads to a compiler error), JetBrains Rider detects the error and suggests fixing it by removing the 'readonly' keyword from the field:

Make non-readonly fix

Another option to make fields readonly in a bulk mode is code cleanup. You can either run code cleanup with the Built-in: Full Cleanup profile or create and run a custom profile solely targeted at your specific task as described below.

Add the 'readonly' keyword to fields that only have read access

  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 Make field read-only, if possible 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 by choosing this layer from the Save selector. For more information, see layer-based settings.

  5. Select the scope where you want to make fields readonly:

    • Place the caret anywhere in the file to make fields readonly to the file.

    • Select one or more items in the Solution Explorer to make fields readonly in the files under these nodes and their child items.

  6. Press Ctrl+R, 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 make fields readonly in the selected scope.

If you want to make fields readonly without opening the Reformat and Cleanup Code dialog to choose a profile, you can bind the created profile to the silent cleanup and run it by pressing Ctrl+R, G. You can also create a custom cleanup profile that would combine making fields readonly with other code style tasks.

Last modified: 01 March 2024