.NET Framework Class Library
HelpKeywordAttribute Class

Specifies the context keyword for a class or member. This class cannot be inherited.

Inheritance Hierarchy
SystemObject
   SystemAttribute
    System.ComponentModel.DesignHelpKeywordAttribute

Namespace:   System.ComponentModel.Design
Assembly:  System (in System.dll)
Syntax
<[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_0_0_0%]> _
<[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_0_0_1%]([%$TOPIC/8faz9d3b_en-us_VS_110_2_0_0_0_2%].All, AllowMultiple := False, Inherited := False)> _
Public NotInheritable Class HelpKeywordAttribute _
	Inherits [%$TOPIC/8faz9d3b_en-us_VS_110_2_0_0_0_3%]
[[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_1_0_0%]]
[[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_1_0_1%]([%$TOPIC/8faz9d3b_en-us_VS_110_2_0_1_0_2%].All, AllowMultiple = false, Inherited = false)]
public sealed class HelpKeywordAttribute : [%$TOPIC/8faz9d3b_en-us_VS_110_2_0_1_0_3%]
[[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_2_0_0%]]
[[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_2_0_1%]([%$TOPIC/8faz9d3b_en-us_VS_110_2_0_2_0_2%]::All, AllowMultiple = false, Inherited = false)]
public ref class HelpKeywordAttribute sealed : public [%$TOPIC/8faz9d3b_en-us_VS_110_2_0_2_0_3%]
[<[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_3_0_0%]>]
[<[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_3_0_1%]>]
[<[%$TOPIC/8faz9d3b_en-us_VS_110_2_0_3_0_2%]([%$TOPIC/8faz9d3b_en-us_VS_110_2_0_3_0_3%].All, AllowMultiple = false, Inherited = false)>]
type HelpKeywordAttribute =  
    class 
        inherit [%$TOPIC/8faz9d3b_en-us_VS_110_2_0_3_0_4%] 
    end

The HelpKeywordAttribute type exposes the following members.

Constructors
  NameDescription
Public method HelpKeywordAttributeInitializes a new instance of the HelpKeywordAttribute class.
Public method HelpKeywordAttribute(String)Initializes a new instance of the HelpKeywordAttribute class.
Public method HelpKeywordAttribute(Type)Initializes a new instance of the HelpKeywordAttribute class from the given type.
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Properties
  NameDescription
Public property HelpKeywordGets the Help keyword supplied by this attribute.
Public property TypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
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Methods
  NameDescription
Public method EqualsDetermines whether two HelpKeywordAttribute instances are equal. (Overrides AttributeEquals(Object).)
Public method GetHashCodeReturns the hash code for this instance. (Overrides AttributeGetHashCode.)
Public method GetTypeGets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttributeDetermines whether the Help keyword is . (Overrides AttributeIsDefaultAttribute.)
Public method MatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public method ToStringReturns a string that represents the current object. (Inherited from Object.)
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Fields
  NameDescription
Public field Static member DefaultRepresents the default value for HelpKeywordAttribute. This field is read-only.
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Explicit Interface Implementations
  NameDescription
Explicit interface implemetation Private method _AttributeGetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeInvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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Remarks

By default, the Help keyword for a class is given by the TypeFullName property value. For members, the Help keyword is given by the full name of the type that declared the property, plus the property name itself.

For example, consider the ControlText property on the System.Windows.FormsButton control. The class keyword is "System.Windows.Forms.Button", but the ControlText property keyword is "System.Windows.Forms.Control.Text", because the ControlText property is declared on the System.Windows.FormsControl class, rather than the System.Windows.FormsButton class itself; the System.Windows.FormsButton class inherits the property.

By contrast, the ButtonDialogResult property is declared on the System.Windows.FormsButton class, so its keyword is "System.Windows.Forms.Button.DialogResult".

When the Help system gets the keywords, it will first look at HelpKeywordAttribute. At the class level, it will return the string specified by the HelpKeywordAttribute. This will not be used for members of the type in question, which will still reflect the declaring type's actual full name, plus the member name. This attribute supports strongly typed classes that have associated common documentation but distinct Help IDs.

Examples

The following code example shows how to override this Help system behavior by placing the attribute on the member itself. These are the keywords for the following class, called DemoComponent:

  • Class keyword: "System.ComponentModel.Component" (DemoNamespace.DemoComponent)

  • Property1 keyword: "DemoNamespace.DemoComponent.Property1" (default)

  • Property2 keyword: "SomeNamespace.SomeOtherClass.Property2" (DemoNamespace.DemoComponent.Property2)

[HelpKeywordAttribute(typeof(Component))]
public class DemoComponent : Component
{
    public string Property1
    {
        get
        {
            return "";
        }
    }

    [HelpKeywordAttribute("SomeNamespace.SomeOtherClass.Property2")]
    public string Property2
    {
        get
        {
            return "";
        }
    }
}

The following code example demonstrates using the HelpKeywordAttribute class to specify a context keyword. For a complete explanation of this code example, see How to: Apply Attributes in Windows Forms Controls.

' This control demonstrates a simple logging capability. 
<ComplexBindingProperties("DataSource", "DataMember"), _
DefaultBindingProperty("TitleText"), _
DefaultEvent("ThresholdExceeded"), _
DefaultProperty("Threshold"), _
HelpKeywordAttribute(GetType(UserControl)), _
ToolboxItem("System.Windows.Forms.Design.AutoSizeToolboxItem,System.Design")> _
Public Class AttributesDemoControl
    Inherits UserControl
// This control demonstrates a simple logging capability. 
[ComplexBindingProperties("DataSource", "DataMember")]
[DefaultBindingProperty("TitleText")]
[DefaultEvent("ThresholdExceeded")]
[DefaultProperty("Threshold")]
[HelpKeywordAttribute(typeof(UserControl))]
[ToolboxItem("System.Windows.Forms.Design.AutoSizeToolboxItem,System.Design")]
public class AttributesDemoControl : UserControl
{
Version Information

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
Platforms

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.