Generating Equality Members
Alt+Insert | Equality Members
The default implementation of equality methods (i.e.
GetHashCode()) as well as equality operators (i.e.
!=) in .NET supports reference equality for reference types.
If you derive your type from a reference type, you may want to implement value equality for
objects of this type and use the hashcode as a unique object identifier for hashing purposes.
In this case, you need to override equality methods and operators for your type.
ReSharper allows you to automate these routines with the Generate equality members command.
In the example below, this command is used to generate
GetHashCode() methods based on
|Before generation||After generation|
To generate equality members for your type
- In the editor, set the caret within a type, at the line where you want to insert overrides for equality members.
- Press Alt+Insert or choose in the main menu .
- In the Generate pop-up menu, select Equality Members.
In the Generate dialog box that appears, select fields to be compared within the
Equals()method and to be included into the value generation in the
If you do not select any fields, ReSharper, depending on your settings, throws new
NotImplementedException(), returns default value, or puts code that will not compile in the body of the generated
GetHashCode()methods. You can configure the settings on the Code Editing | Members Generation options page.
Optionally, use the following controls:
Overload equality operators
generates custom equality and inequality operators (i.e.
!=) for the current type.
Implement IEquatable<T> interface
implements a type-specific
GetHashCode already exists
Equals already exists
appear if the corresponding overrides already exist and let you indicate whether to:
- Replace the corresponding override if it already exists.
- Put the newly generated override side by side with the existing override.
- Skip generating a new override altogether.
Comparand type check
allows you to choose how the
Equals()method will compare object types:
- Type exactly same as this
- Type exactly as the owner type
- Type is of the owner type or a subtype
- Overload equality operators generates custom equality and inequality operators (i.e.
to complete the wizard.
You can also click Options to review or modify commmon code generation preferences on the Code Editing | Members Generation page of ReSharper options
You can also generate the two overrides by choosing Overriding Members in the Generate menu, but in that case they will both return base methods.
As an alternative to generating equality members within your type, you can generate equality comparer class for your type.
This feature is supported in the following languages/technologies:
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.