this and Me preferences (IDE0003 and IDE0009)

Article
10/20/2022

This article describes two related rules, IDE0003 and IDE0009.

Property	Value
Rule ID	IDE0003
Title	Remove `this` or `Me` qualification
Category	Style
Subcategory	Language rules ('this.' and 'Me.' qualifiers)
Applicable languages	C# and Visual Basic
Options	`dotnet_style_qualification_for_field`
	`dotnet_style_qualification_for_property`
	`dotnet_style_qualification_for_method`
	`dotnet_style_qualification_for_event`

Property	Value
Rule ID	IDE0009
Title	Add `this` or `Me` qualification
Category	Style
Subcategory	Language rules ('this.' and 'Me.' qualifiers)
Applicable languages	C# and Visual Basic
Options	`dotnet_style_qualification_for_field`
	`dotnet_style_qualification_for_property`
	`dotnet_style_qualification_for_method`
	`dotnet_style_qualification_for_event`

Overview

These two rules define whether or not you prefer the use of this (C#) and Me. (Visual Basic) qualifiers. To enforce that the qualifiers aren't present, set the severity of IDE0003 to warning or error. To enforce that the qualifiers are present, set the severity of IDE0009 to warning or error.

For example, if you prefer qualifiers for fields and properties but not for methods or events, then you can enable IDE0009 and set the options dotnet_style_qualification_for_field and dotnet_style_qualification_for_property to true. However, this configuration would not flag methods and events that do have this and Me qualifiers. To also enforce that methods and events don't have qualifiers, enable IDE0003.

Options

This rule's associated options define which of the following symbols this style preference should be applied to:

Fields (dotnet_style_qualification_for_field)
Properties (dotnet_style_qualification_for_property)
Methods (dotnet_style_qualification_for_method)
Events (dotnet_style_qualification_for_event)

An option value of true means prefer the code symbol to be prefaced with this. in C# and Me. in Visual Basic. An option value of false means prefer the code element not to be prefaced with this. or Me..

For more information about configuring options, see Option format.

dotnet_style_qualification_for_field

Property	Value	Description
Option name	dotnet_style_qualification_for_field
Option values	`true`	Prefer fields to be prefaced with `this.` in C# or `Me.` in Visual Basic
	`false`	Prefer fields not to be prefaced with `this.` or `Me.`
Default option value	`false`

// dotnet_style_qualification_for_field = true
this.capacity = 0;

// dotnet_style_qualification_for_field = false
capacity = 0;

' dotnet_style_qualification_for_field = true
Me.capacity = 0

' dotnet_style_qualification_for_field = false
capacity = 0

dotnet_style_qualification_for_property

Property	Value	Description
Option name	dotnet_style_qualification_for_property
Option values	`true`	Prefer properties to be prefaced with `this.` in C# or `Me.` in Visual Basic.
	`false`	Prefer properties not to be prefaced with `this.` or `Me.`.
Default option value	`false`

// dotnet_style_qualification_for_property = true
this.ID = 0;

// dotnet_style_qualification_for_property = false
ID = 0;

' dotnet_style_qualification_for_property = true
Me.ID = 0

' dotnet_style_qualification_for_property = false
ID = 0

dotnet_style_qualification_for_method

Property	Value	Description
Option name	dotnet_style_qualification_for_method
Option values	`true`	Prefer methods to be prefaced with `this.` in C# or `Me.` in Visual Basic.
	`false`	Prefer methods not to be prefaced with `this.` or `Me.`.
Default option value	`false`

// dotnet_style_qualification_for_method = true
this.Display();

// dotnet_style_qualification_for_method = false
Display();

' dotnet_style_qualification_for_method = true
Me.Display()

' dotnet_style_qualification_for_method = false
Display()

dotnet_style_qualification_for_event

Property	Value	Description
Option name	dotnet_style_qualification_for_event
Option values	`true`	Prefer events to be prefaced with `this.` in C# or `Me.` in Visual Basic.
	`false`	Prefer events not to be prefaced with `this.` or `Me.`.
Default option value	`false`

// dotnet_style_qualification_for_event = true
this.Elapsed += Handler;

// dotnet_style_qualification_for_event = false
Elapsed += Handler;

' dotnet_style_qualification_for_event = true
AddHandler Me.Elapsed, AddressOf Handler

' dotnet_style_qualification_for_event = false
AddHandler Elapsed, AddressOf Handler

Suppress a warning

If you want to suppress only a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable IDE0003 // Or IDE0009
// The code that's violating the rule is on this line.
#pragma warning restore IDE0003 // Or IDE0009

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.{cs,vb}]
dotnet_diagnostic.IDE0003.severity = none
dotnet_diagnostic.IDE0009.severity = none

To disable all of the code-style rules, set the severity for the category Style to none in the configuration file.

[*.{cs,vb}]
dotnet_analyzer_diagnostic.category-Style.severity = none

For more information, see How to suppress code analysis warnings.