VerificationAttribute Class
Defines the metadata attribute of a Web content accessibility rule. This class cannot be inherited.
Assembly: System.Web (in System.Web.dll)
The VerificationAttribute type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | VerificationAttribute(String, String, VerificationReportLevel, Int32, String) | Initializes a new instance of the VerificationAttribute class with accessibility guideline, checkpoint, reporting level, checkpoint priority, and error message. |
![]() | VerificationAttribute(String, String, VerificationReportLevel, Int32, String, VerificationRule, String) | Initializes a new instance of the VerificationAttribute class with accessibility guideline, checkpoint, reporting level, checkpoint priority, error message, VerificationRule.value, and related conditional property. |
![]() | VerificationAttribute(String, String, VerificationReportLevel, Int32, String, VerificationRule, String, VerificationConditionalOperator, String, String) | Initializes a new instance of the VerificationAttribute class with accessibility guideline, checkpoint, reporting level, checkpoint priority, error message, VerificationRule.value, related conditional property, a related conditional property value, and a reference guideline URL. |
| Name | Description | |
|---|---|---|
![]() | Checkpoint | Gets the accessibility checkpoint reference in the specified Guideline property. |
![]() | ConditionalProperty | Gets the left side of a conditional expression used as part of the verification accessibility checkpoint. |
![]() | ConditionalValue | Gets the right side of a conditional expression used as part of the verification accessibility checkpoint. |
![]() | Guideline | Gets the guideline that used for accessibility checking. |
![]() | GuidelineUrl | Gets the URL the can be used to get more information on the accessibility guidelines given in the Guideline property. |
![]() | Message | Gets a message string when the accessibility checkpoint verification rule is true. |
![]() | Priority | Gets the priority of the accessibility checkpoint. |
![]() | TypeId | When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.) |
![]() | VerificationConditionalOperator | Gets a VerificationConditionalOperator enumeration value indication how the accessibility checkpoint is verified. |
![]() | VerificationReportLevel | Gets a VerificationReportLevel enumeration value indicating how the accessibility checkpoint is used. |
![]() | VerificationRule | Gets a VerificationRule enumeration value indicating how the accessibility checkpoint is used. |
| Name | Description | |
|---|---|---|
![]() | Equals | Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetHashCode | Returns the hash code for this instance. (Inherited from Attribute.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | IsDefaultAttribute | When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.) |
![]() | Match | When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.) |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
| Name | Description | |
|---|---|---|
![]() ![]() | _Attribute::GetIDsOfNames | Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.) |
![]() ![]() | _Attribute::GetTypeInfo | Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.) |
![]() ![]() | _Attribute::GetTypeInfoCount | Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.) |
![]() ![]() | _Attribute::Invoke | Provides access to properties and methods exposed by an object. (Inherited from Attribute.) |
An instance of the VerificationAttribute class defines a Web content accessibility rule that can be verified. For more information on Web Content Accessibility Guidelines, see the World Wide Web Consortium (W3C) Web site.
The minimal amount of information required to define an instance of a VerificationAttribute includes:
A guideline that the verification rule represents. The value specified in the constructor sets the Guideline property.
A checkpoint of the guideline. The value specified in the constructor sets the Checkpoint property.
A checkpoint priority. The value specified in the constructor sets the Priority property.
A VerificationReportLevel enumeration value that represents the reporting level that should be rule belongs to. The value specified in the constructor sets the VerificationReportLevel property.
A message that is reported when the verification rule is true. The value specified in the constructor sets the Message property.
Optional properties of the verification rule that can be specified when creating an instance:
A VerificationRule enumeration value that represents how the verification rule should be interpreted. The value specified in the constructor sets the VerificationRule property.
A VerificationConditionalOperator enumeration value that represents the operator in the conditional expression used to test the verification rule. The value specified in the constructor sets the VerificationConditionalOperator property.
An accessibility reference guideline URL. The value specified in the constructor sets the GuidelineUrl property.
A conditional value representing the right side of a conditional expression. The value specified in the constructor sets the ConditionalValue property.
A conditional property representing the left side of a conditional expression. The value specified in the constructor sets the ConditionalProperty property.
The VerificationAttribute metadata can be defined class, property, and indexer declarations.
For more information about using attributes, see Extending Metadata Using Attributes.
The following code example demonstrates using the VerificationAttribute class. In the verification metadata definition, the guidelines used are "WCAG," the Web Content Accessibility Guideline, and "ADA," Americans with Disabilities Act Guidelines. For more information, see the World Wide Web Consortium (W3C) Web site.
The checkpoints used are "1.1" and "1194.22(a)" for WCAG and ADA, respectively, checkpoints for ensuring that a text equivalent exists for non-text elements. The VerificationAttribute is applied to the ImageText property that represents the text equivalent of another property called ImageProperty. If the ImageText property is not set, the accessibility verification will return the message "The image is missing a text equivalent."
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.




