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Implicit/Explicit Typing

Using implicitly typed local variables (also known as var keyword) introduced in C# 3.0 has become quite popular due to improved readability of the resulting code. By default, ReSharper also encourages using of var keyword, but the preferences of its using it are flexibly configurable. For example, you can opt for using explicit types in specific cases or everywhere.

In this topic:

Configuring preferences of using 'var' keyword

Your 'var' keyword usage preferences are saved using the mechanism of shared 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.

To configure preferences of using var keyword

  1. Go to ReSharper | Options | Code Editing | C# | Code Style.
  2. Modify settings in the 'var' usage in declarations category according to your coding practices/standards.
  3. The Notify with selectors in the right column allow you to set severity levels of code inspections detecting code that differs from your preferences.
  4. If you do not want ReSharper to check and enforce some preferences, you can disable them by setting their severity levels to Do not show.
  5. Click Save to apply the modifications and let ReSharper choose where to save them, or save the modifications to a specific settings layer using the Save To drop-down list. For more information, see Managing and Sharing ReSharper Settings.

Enforcing preferences of using 'var' keyword

By default, all variables declared at method scope are checked for compliance with your preferences and if they do not comply, ReSharper highlights such declarations and suggests the corresponding quick-fix or fix in scope.

Your preferences may say that 'var' keyword is preferred:

'Var' usage quick-fix
... or that explicit types should be used:
'Var' usage quick-fix

Another option to enforce preferences of 'var' keyword usage in a bulk mode is code cleanup. You can either run code cleanup with the default profile Default: Full Cleanup or run the cleanup with a custom profile solely targeted at your specific task as described below.

To apply preferences of using var keyword with code cleanup

  1. Open the Code Cleanup options: ReSharper | Options | Code Editing | Code Cleanup.
  2. Create a new profile as described in the Configuring Code Clenup section. In the Selected profile settings section for the new profile tick the Enforce 'var' keyword usage settings check box.
  3. Click Save to apply the modifications and let ReSharper choose where to save them, or save the modifications to a specific settings layer using the Save To drop-down list. For more information, see Managing and Sharing ReSharper Settings.
  4. 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.
  5. Do one of the following:
    • Choose ReSharper | Tools | Cleanup Code on the main menu.
    • Press Ctrl+Alt+F.
    • Right-click anywhere in the text editor or right-click the selection and choose Cleanup Code in the context menu.
  6. In the Code Cleanup dialog box that opens, select the newly created profile in the Available Profiles area.
  7. Click Run. ReSharper will enforce your preferences in the selected scope according to your preferences.

If you want to enforce 'var' keyword usage setting without opening the Code Cleanup dialog box, you can bind the created profile to the silent cleanup and run it simply by pressing Ctrl+Shift+Alt+F. You can also create a custom cleanup profile that would combine applying the preferences with other code style tasks.

This feature is supported in the following languages/technologies:

C# VB.NET C++ HTML ASPX Razor JavaScript TypeScript CSS XML XAML RESX Build Scripts
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The instructions and examples given here address the use of the feature in C#. For details specific to other languages, see corresponding topics in the ReSharper by Language section. Specifically:

See Also

Last modified: 21 September 2015