QueryAccessibilityHelpEventArgs Class
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Provides data for the QueryAccessibilityHelp event.
public ref class QueryAccessibilityHelpEventArgs : EventArgs
[System.Runtime.InteropServices.ComVisible(true)]
public class QueryAccessibilityHelpEventArgs : EventArgs
public class QueryAccessibilityHelpEventArgs : EventArgs
[<System.Runtime.InteropServices.ComVisible(true)>]
type QueryAccessibilityHelpEventArgs = class
inherit EventArgs
type QueryAccessibilityHelpEventArgs = class
inherit EventArgs
Public Class QueryAccessibilityHelpEventArgs
Inherits EventArgs
- Inheritance
- Attributes
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.
// Handles the QueryAccessibilityHelp event.
void ChartControl_QueryAccessibilityHelp( Object^ /*sender*/, System::Windows::Forms::QueryAccessibilityHelpEventArgs^ e )
{
e->HelpString = "Displays chart data";
}
// Handles the QueryAccessibilityHelp event.
private void ChartControl_QueryAccessibilityHelp(object sender,
System.Windows.Forms.QueryAccessibilityHelpEventArgs e)
{
e.HelpString = "Displays chart data";
}
' Handle the QueryAccessibilityHelp event.
Private Sub ChartControl_QueryAccessibilityHelp(sender As Object, _
e As System.Windows.Forms.QueryAccessibilityHelpEventArgs) Handles MyBase.QueryAccessibilityHelp
e.HelpString = "Displays chart data"
End Sub
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.
Note
The HelpKeyword property should be a string representation of a numeric Help topic ID.
Query |
Initializes a new instance of the QueryAccessibilityHelpEventArgs class. |
Query |
Initializes a new instance of the QueryAccessibilityHelpEventArgs class. |
Help |
Gets or sets the Help keyword for the specified control. |
Help |
Gets or sets a value specifying the name of the Help file. |
Help |
Gets or sets the string defining what Help to get for the AccessibleObject. |
Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
Get |
Serves as the default hash function. (Inherited from Object) |
Get |
Gets the Type of the current instance. (Inherited from Object) |
Memberwise |
Creates a shallow copy of the current Object. (Inherited from Object) |
To |
Returns a string that represents the current object. (Inherited from Object) |
Product | Versions |
---|---|
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
Windows Desktop | 3.0, 3.1, 5, 6, 7, 8, 9 |
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