ReSharper 2019.1 Help

Code Syntax Style: Namespace Imports

In each of your source code files, you should have the right set of namespace imports (using directives in C#). If an import is missing, your code does not compile, if there are unused imports, they could make maintaining your code difficult over time. Moreover, there are different approaches to importing namespaces, for example, you can either add using directives or use fully qualified type names, you can place using directives on top of the file or inside a namespace, and so on.

ReSharper provides a number of features to help you control and automatically update all aspects of importing namespaces according to your preferences.

Configuring namespace imports preferences

Your namespace imports 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.

To configure namespace imports preferences

  1. Select ReSharper | Options in the main menu or press Alt+R,,O, then choose Code Editing | C# | Namespace Imports on the left.

  2. On this options page, you can specify namespaces that should never be removed and/or namespaces that should be always imported.

  3. Open the Code Editing | C# | Code Style page of ReSharper options.

  4. Use preferences in the Reference qualification and 'using' directives group to fine-tune namespace import style:

    • Prefer fully qualified references — select this checkbox if you prefer use fully qualified names rather than namespace import directives for imported types.

    • Add 'using' directive to the deepest scope — if this checkbox is selected, namespace import directives are added inside the namespace where the imported types are used; otherwise the import directives are added in the top of the file.

    • Place 'System.*' and 'Windows.*' namespaces first when sorting 'using' directives — if this checkbox is selected, 'using' directives like using System.Linq; will be placed above other using directives when sorting. Otherwise, these directive will sorted alphabetically with others.

    • Prefer fully qualified using name at nested scope — if this checkbox is selected, fully qualified names for imported types are preferred in nested types and namespaces.

    • Allow using alias directive — selecting this checkbox allows using aliases in namespace import directives, as opposed to fully qualified namespace names.

    • Allow the 'global::' prefix — if this checkbox is selected, the global:: prefix are not removed, as in global::System.String. For more information, see How to: Use the Global Namespace Alias.

  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 list. For more information, see managing and sharing resharper settings.

Importing missing namespaces

ReSharper helps you detect symbols with missing namespace imports and add proper imports automatically. An unresolved symbol is immediately highlighted in the editor and the corresponding fix is suggested:

Namespace import quick-fix
If there are several unresolved symbols in the file, the fix adds imports for all of them. The imports are added according to the configured preferences of namespace imports. For more information, see Importing Missing Namespaces.

Removing redundant namespace imports and optimizing existing ones

Any imported namespace becomes redundant in your code if you remove usages of namespace symbols. Without ReSharper, you have to scroll to the top of every file, find unused namespace import directives, and remove them. ReSharper makes life a lot easier by allowing you to automatically remove unused namespace import directives from your file, project or solution. Besides removing redundant namespace imports, ReSharper can optimize them in several ways according to your namespace imports preferences.

All redundant namespace imports are highlighted are the editor and the corresponding quick-fixes are suggested including fix in scope:

Unused namespace import quick-fix
By applying suggested fixes you can remove redundant namespaces instantly in the desired scope.

Another option to remove redundant namespace imports 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.

In contrast to quick-fixes, code cleanup not only removes unused imports but also optimizes existing imports according to your preferences. For example, using the code cleanup you can replace fully qualified type names with plain type names by adding the corresponding namespace imports.

To optimize namespace imports using Code Cleanup

  1. Select ReSharper | Options in the main menu or press Alt+R,,O.

  2. Go to the Code Cleanup settings page: Code Editing | Code Cleanup.

  3. Create a new profile as described in the To create a new custom cleanup profile section. In the Selected profile settings for the new profile:
    • Select Optimize 'using' directives.

    • Optionally, to embrace unused using directives in a region, select Embrace 'using' directives in region and specify the name of the region in the Region name field.

  4. 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 list. For more information, see managing and sharing resharper settings.

  5. Select the scope where you want to optimize namespace imports:
    • Set the caret anywhere in the file to optimize namespace imports to the file.

    • Select one or more items in the Solution Explorer to optimize namespace imports in the files under these nodes and their child items.

  6. Do one of the following:
    • Press Ctrl+Alt+F or choose ReSharper | Edit | Cleanup Code from the main menu.

    • Right-click anywhere in the text editor or right-click the selection and choose Cleanup Code in the context menu.

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

  8. Click Run. ReSharper will optimize namespace imports in the selected scope.

If you want to optimize namespace imports without opening the Code Cleanup dialog, 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 optimizing namespace imports with other code style tasks.

This feature is supported in the following languages and technologies:

Language: C# Language: VB.NET Language: C++ Language: HTML Language: ASP.NET Language: Razor Language: JavaScript Language: TypeScript Language: CSS Language: XML Language: XAML Language: Resx Language: Build Scripts Language: Protobuf Language: JSON
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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.

Last modified: 26 June 2019

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