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QueryAccessibilityHelpEventArgs Class

Provides data for the QueryAccessibilityHelp event.

System.Object
  System.EventArgs
    System.Windows.Forms.QueryAccessibilityHelpEventArgs

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

[<ComVisibleAttribute(true)>]
type QueryAccessibilityHelpEventArgs =  
    class 
        inherit EventArgs 
    end

The QueryAccessibilityHelpEventArgs type exposes the following members.

  NameDescription
Public methodQueryAccessibilityHelpEventArgs()Initializes a new instance of the QueryAccessibilityHelpEventArgs class.
Public methodQueryAccessibilityHelpEventArgs(String, String, String)Initializes a new instance of the QueryAccessibilityHelpEventArgs class.
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  NameDescription
Public propertyHelpKeywordGets or sets the Help keyword for the specified control.
Public propertyHelpNamespaceGets or sets a value specifying the name of the Help file.
Public propertyHelpStringGets or sets the string defining what Help to get for the AccessibleObject.
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  NameDescription
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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The Control class exposes a public QueryAccessibilityHelp event. You can use the properties of the QueryAccessibilityHelpEventArgs class to return custom help for a particular control to an accessible client, such as a screen reader. When you handle the QueryAccessibilityHelp event, you must set the values of the HelpNamespace, HelpKeyword, and HelpString properties to appropriate values.

NoteNote

The HelpKeyword property should be a string representation of a numeric Help topic ID.

The following code example demonstrates the creation of an accessibility-aware chart control, using the AccessibleObject and Control.ControlAccessibleObject classes to expose accessible information. The control plots two curves along with a legend. The ChartControlAccessibleObject class, which derives from ControlAccessibleObject, is used in the CreateAccessibilityInstance method to provide custom accessible information for the chart control. Because the chart legend is not an actual Control-based control, but instead is drawn by the chart control, it does not any built-in accessible information. Because of this, the ChartControlAccessibleObject class overrides the GetChild method to return the CurveLegendAccessibleObject that represents accessible information for each part of the legend. When an accessible-aware application uses this control, the control can provide the necessary accessible information.

This example demonstrates using the QueryAccessibilityHelpEventArgs class with the QueryAccessibilityHelp event. See the AccessibleObject class overview for the complete code example.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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.

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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