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Control.CreateAccessibilityInstance Method

Creates a new accessibility object for the control.

[Visual Basic]
Protected Overridable Function CreateAccessibilityInstance() As _
   AccessibleObject
[C#]
protected virtual AccessibleObject CreateAccessibilityInstance();
[C++]
protected: virtual AccessibleObject* CreateAccessibilityInstance();
[JScript]
protected function CreateAccessibilityInstance() : AccessibleObject;

Return Value

A new AccessibleObject for the control.

Remarks

If you do not explicitly call the CreateAccessibilityInstance method, it will be called when the AccessibilityObject property is referenced.

Note   To get or set the AccessibilityObject property, you must add a reference to the Accessibility assembly installed with the .NET Framework.

Notes to Inheritors:  When overriding CreateAccessibilityInstance in a derived class, you should not call the base class's CreateAccessibilityInstance method.

Example

[Visual Basic, C#, C++] The following 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. Since 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.

[Visual Basic, C#, C++] This code excerpt demonstrates overriding the CreateAccessibilityInstance method. See the AccessibleObject class overview for the complete code example.

[Visual Basic] 
' Overridden to return the custom AccessibleObject 
' for the entire chart.
Protected Overrides Function CreateAccessibilityInstance() As AccessibleObject
    Return New ChartControlAccessibleObject(Me)
End Function 

[C#] 
// Overridden to return the custom AccessibleObject 
// for the entire chart.
protected override AccessibleObject CreateAccessibilityInstance() 
{            
    return new ChartControlAccessibleObject(this);
}

[C++] 
// Overridden to return the custom AccessibleObject
// for the entire chart.
protected:
AccessibleObject* CreateAccessibilityInstance() {
   return new ChartControlAccessibleObject(this);
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

Control Class | Control Members | System.Windows.Forms Namespace | Control.ControlAccessibleObject | AccessibleObject

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