ReSharper 2019.2 Help

Examples of Quick-Fixes

Quick-fixes are available in a variety of circumstances, which is too large to be listed. ReSharper provides a total of more than 1200 quick-fixes in all supported languages. Here we will show how to use them using a small selection of situations:

Type mismatch

Whenever the type of an expression cannot be implicitly cast to the type applicable to the expression context, ReSharper detects this error and highlights it in the editor. After positioning the caret at the highlighted error and pressing Alt+Enter, you can choose a quick-fix from the following list:

ReSharper: Type mismatch quick-fix

The effects of applying the proposed quick-fixes are illustrated in the table below.

Quick-fix

Effect

Cast to string

ReSharper: Type mismatch quick-fix

Safely cast to string

ReSharper: Type mismatch quick-fix

Change type of o to string

ReSharper: Type mismatch quick-fix

Change type of s to object

ReSharper: Type mismatch quick-fix

Call ToString()

ReSharper: Type mismatch quick-fix

Undefined variable

Whenever ReSharper detects an undefined variable in your code, the error is highlighted. After positioning the caret at the highlighted error and pressing Alt+Enter you will be presented with the following list of quick-fixes:

ReSharper: Undefined variable quick-fix

The effects of applying the proposed quick-fixes are illustrated in the table below.

Quick-fix

Effect

Create local variable s

A new local variable s is created proposing you to choose the desired type.

Create parameter s in the containing method

A new parameter is added to the method signature:

ReSharper: Undefined variable quick-fix

Create other

Opens a sub-menu where you can choose to create a field or a property in the corresponding class. For example, if you choose to create a field, a new private field s is created in the current class. The following suggestion appears helping you to choose the correct type of the new field:

ReSharper: Undefined variable quick-fix

Change all s

If you choose Change all, the following suggestion displays:

ReSharper: Undefined variable quick-fix

Type the new name only once; ReSharper changes all the other occurrences of the undefined variable:

ReSharper: Undefined variable quick-fix

Undefined method call

Whenever ReSharper detects a call to an undefined method in your code, the error gets highlighted. After positioning the caret at the highlighted error and pressing Alt+Enter, ReSharper displays the following list of quick-fixes:

ReSharper: Undefined method call quick-fix

After applying a quick-fix, the code gets modified as shown in the following table:

Quick-fix

Effect

Create method ResolveManagedReference

This quick-fix declares a new method with the signature derived from the method call, benefiting developers who prefer top-down programming. In our example, ReSharper creates the following declaration, correctly guessing the return type:

ReSharper: Undefined method call quick-fix

ReSharper also suggests applicable types and a name for the parameter of the new method:

ReSharper: Undefined method call quick-fix

Create other

This sub-menu includes other quick-fixes involving creation of auxiliary code. For example:

  • Create parameter ResolveManagedReference in containing method and update hierarchy.
    This quick-fix creates a new parameter in the current method from the unresolved symbol, and introduces this parameter into any base members and inheritors that the method may have.

  • Create parameter ResolveManagedReference in containing method
    This quick-fix creates a new parameter in the current method from the unresolved symbol but doesn't update its base methods or inheritors.

Change all ResolveManagedReference

Similarly to the corresponding quick-fix for undefined variables, this quick-fix allows you to quickly replace all occurrences of the symbol someMethod.

Forgotten method return

If a method is expected to return a value but you forgot to provide a return statement, ReSharper warns you about that by highlighting the closing bracket of the troublesome method. After positioning the caret at the highlighted error and pressing Alt+Enter you will be presented with the following quick-fixes:

ReSharper: Forgotten method return quick-fix

Quick-fix

Effect

Add return statement

After the quick-fix is applied, ReSharper adds a return statement returning null.

Make method return void

After the quick-fix is applied, ReSharper replaces the initial return type of the method with void.

Missing Using directives

Whenever you have a type name in your code that cannot be resolved because you forgot to write a corresponding using directive in your file, a small popup suggests to import the type:

ReSharper: Namespace import quick-fix

Press Alt+Enter, and the appropriate using directive will be inserted. Should there be multiple types with the matching name, you will be asked to choose the one you wish to use (see Importing Namespaces for details).

If for some reason you chose not to import a required namespace when the popup was displayed, or if you cleared the Show the "Import namespace" action using popup checkbox on the Code Inspection | Settings page of ReSharper options, you can import a type at any time by putting the caret at the non-imported type, pressing Alt+Enter and choosing the corresponding quick-fix.

ReSharper: quick-fixes for missing namespace import

You may want some symbols not to be suggested, for example, if you have something similar to a system type in your solution, say MyFramework.MyCollections.List, but you are not actually using it. To exclude such symbols from the suggestions, add them to the Exclude from import and completion list on the Code Inspection | Settings | Auto Import page of ReSharper options (Alt+R,,O). The format of the entries is Fully.Qualified.Name, Fully.Qualified.Name.Prefix*, or *Fully.Qualified.Name.Suffix. Generic types are specified as List`1.

Missing async modifier

If you have a method that contains the await operator, but that is not defined as asynchronous, ReSharper detects such mismatch and offers to fix this problem using the corresponding quick-fix.

Before:

ReSharper: Missing async modifier quick-fix

Applying the quick-fix:

ReSharper: Missing async modifier quick-fix

After:

ReSharper: Missing async modifier quick-fix

Converting a loop to a LINQ expression

With C# 3.0 and LINQ, developers are able to write data-intensive code more easily by directly describing their intent to the compiler. ReSharper detects code that can be rewritten using LINQ syntax and offers to perform the conversion automatically:

Before:

ReSharper: Converting a loop to a LINQ expression quick-fix

Applying the quick-fix:

ReSharper: Converting a loop to a LINQ expression quick-fix

After:

ReSharper: Converting a loop to a LINQ expression quick-fix

Migrating to IEnumerable in method parameters and returns

ReSharper scans your code base to detect methods that can safely return and accept IEnumerable instead of a more specific type such as Array, List, or ArrayList:

Before:

ReSharper: Migrating to IEnumerable in method parameters and returns

Applying the quick-fix:

ReSharper: Migrating to IEnumerable in method parameters and returns

After:

ReSharper: Migrating to IEnumerable in method parameters and returns

Converting assignment statements to object initializers

ReSharper provides both a context action and a quick-fix to convert assignment statements into object initializers. The context action lets you add field assignments to an initializer one-by-one, whereas the quick-fix adds them all in one go. Here's how the quick-fix works:

Before:

ReSharper: Converting assignment statements to object initializers

Applying the quick-fix:

ReSharper: Converting assignment statements to object initializers

After:

ReSharper: Converting assignment statements to object initializers

Converting static method invocation to extension method call

When you invoke an extension method as a traditional C# static method, ReSharper helps you quickly comply with standard extension method call practices:

Before:

ReSharper: Converting static method invocation to extension method call

Applying the quick-fix:

ReSharper: Converting static method invocation to extension method call

After:

ReSharper: Converting static method invocation to extension method call

Converting anonymous method to lambda expression

ReSharper suggests converting anonymous methods to lambda expressions. The reverse functionality is provided as a context action.

Before:

ReSharper: Converting anonymous method to lambda expression

Applying the quick-fix:

ReSharper: Converting anonymous method to lambda expression

After:

ReSharper: Converting anonymous method to lambda expression

Converting to auto-property

ReSharper makes it quick to convert traditional, private field-based properties to automatic properties implemented in C# 3.0. For more information, see Using Auto-Properties.

Before:

ReSharper: Converting to auto-property

Applying the quick-fix:

ReSharper: Converting to auto-property

After:

ReSharper: Converting to auto-property

Making type parameter invariant

When a usage of a type parameter violates its variance, ReSharper suggests to make the parameter invariant:

Before:

ReSharper: Making type parameter invariant

Applying the quick-fix:

ReSharper: Making type parameter invariant

After:

ReSharper: Making type parameter invariant
Last modified: 7 November 2019