HelpKeywordAttribute Class

 

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

Namespace:   System.ComponentModel.Design
Assembly:  System (in System.dll)

System.Object
  System.Attribute
    System.ComponentModel.Design.HelpKeywordAttribute

[SerializableAttribute]
[AttributeUsageAttribute(AttributeTargets.All, AllowMultiple = false, 
	Inherited = false)]
public sealed class HelpKeywordAttribute : Attribute

NameDescription
System_CAPS_pubmethodHelpKeywordAttribute()

Initializes a new instance of the HelpKeywordAttribute class.

System_CAPS_pubmethodHelpKeywordAttribute(String)

Initializes a new instance of the HelpKeywordAttribute class.

System_CAPS_pubmethodHelpKeywordAttribute(Type)

Initializes a new instance of the HelpKeywordAttribute class from the given type.

NameDescription
System_CAPS_pubpropertyHelpKeyword

Gets the Help keyword supplied by this attribute.

System_CAPS_pubpropertyTypeId

When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether two HelpKeywordAttribute instances are equal.(Overrides Attribute.Equals(Object).)

System_CAPS_pubmethodGetHashCode()

Returns the hash code for this instance.(Overrides Attribute.GetHashCode().)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodIsDefaultAttribute()

Determines whether the Help keyword is null.(Overrides Attribute.IsDefaultAttribute().)

System_CAPS_pubmethodMatch(Object)

When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubfieldSystem_CAPS_staticDefault

Represents the default value for HelpKeywordAttribute. This field is read-only.

NameDescription
System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfoCount(UInt32)

Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

By default, the Help keyword for a class is given by the Type.FullName 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 Control.Text property on the System.Windows.Forms.Button control. The class keyword is "System.Windows.Forms.Button", but the Control.Text property keyword is "System.Windows.Forms.Control.Text", because the Control.Text property is declared on the System.Windows.Forms.Control class, rather than the System.Windows.Forms.Button class itself; the System.Windows.Forms.Button class inherits the property.

By contrast, the Button.DialogResult property is declared on the System.Windows.Forms.Button 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.

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(typeof(UserControl))]
[ToolboxItem("System.Windows.Forms.Design.AutoSizeToolboxItem,System.Design")]
public class AttributesDemoControl : UserControl
{

.NET Framework
Available since 2.0

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

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