JetBrains Rider 2020.1 Help

Code Syntax Style: Named/Positional Arguments

If you prefer to use named arguments for specific types of parameters, JetBrains Rider can help you enforce this practice.

Consider the following method call:

AddCheckbox(true, true, "AutoFill", null);

When you read this code, you have to stop and study the method signature to understand what happens here (you can do it either with the parameter information tooltip or by navigating to method declaration). With named arguments, the same call becomes much clearer:

AddCheckbox(enabled: true, value: true, label: "AutoFill", tooltip: null);

If you prefer to have named arguments for specific types, you can enforce this preference with the help of JetBrains Rider.

JetBrains Rider helps you arrange arguments 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.

Apply style preferences for arguments

By default, JetBrains Rider suggests using positional arguments everywhere and you have to explicitly specify which types of parameters require named arguments. According to your preferences, JetBrains Rider highlights positional arguments that require names or named arguments that should be positional, and then suggests the corresponding quick-fix or fix in scope:

Quick fix that help you add or remove argument names

Even if you do not have any style preferences for arguments, you can always press Alt+Enter on any named or positional argument and choose to add or remove the argument name with the corresponding context action:

Context action to add or remove argument names

Another option to enforce preferences for named/positional arguments in a bulk mode is code cleanup. You can either run code cleanup with one of the default 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 argument style 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 Code Cleanup 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 Apply argument style checkbox. Optionally, you can enable other code cleanup tasks in this profile.

  4. Click Save 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. Choose Code | Code Cleanup in the main menu.

  7. In the Code Cleanup dialog that opens, select the newly created profile.

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

Configure preferences for named/positional arguments

Your arguments 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 preferences of arguments style

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

  2. In the Arguments category select whether to use named or positional arguments for specific parameter types. Note that Literal values refers to all literals (bool, int, double, and so on) except strings. The preference for strings is defined in the String literal values selector.
    The category Other applies to all other expression types, like conditional, null-coalescing, binary, invocation or typeof expressions

  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 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.

Last modified: 14 July 2020