編輯

共用方式為

Control.CreateAccessibilityInstance Method

  • Reference

Definition

Namespace:
System.Windows.Forms
Assembly:
System.Windows.Forms.dll
Source:
Control.cs
Source:
Control.cs
Source:
Control.cs

Creates a new accessibility object for the control.

protected:
 virtual System::Windows::Forms::AccessibleObject ^ CreateAccessibilityInstance();
protected virtual System.Windows.Forms.AccessibleObject CreateAccessibilityInstance ();
abstract member CreateAccessibilityInstance : unit -> System.Windows.Forms.AccessibleObject
override this.CreateAccessibilityInstance : unit -> System.Windows.Forms.AccessibleObject
Protected Overridable Function CreateAccessibilityInstance () As AccessibleObject

Returns

AccessibleObject

A new AccessibleObject for the control.

Examples

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. 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.

This code excerpt demonstrates overriding the CreateAccessibilityInstance method. See the AccessibleObject class overview for the complete code example.

protected:
   // Overridden to return the custom AccessibleObject
   // for the entire chart.
   virtual AccessibleObject^ CreateAccessibilityInstance() override
   {
      return gcnew ChartControlAccessibleObject( this );
   }

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

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

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, do not call the base class's CreateAccessibilityInstance() method.

Applies to

See also