AccessibleStates AccessibleStates AccessibleStates AccessibleStates Enum

Definition

Specifies values representing possible states for an accessible object.

This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.

public enum class AccessibleStates
[System.Flags]
public enum AccessibleStates
type AccessibleStates = 
Public Enum AccessibleStates
Inheritance
AccessibleStatesAccessibleStatesAccessibleStatesAccessibleStates
Attributes

Fields

AlertHigh AlertHigh AlertHigh AlertHigh 268435456

The important information that should be conveyed to the user immediately. For example, a battery-level indicator reaching a critical low level would transition to this state, in which case, a blind access utility would announce this information immediately to the user, and a screen magnification program would scroll the screen so that the battery indicator is in view. This state is also appropriate for any prompt or operation that must be completed before the user can continue.

AlertLow AlertLow AlertLow AlertLow 67108864

The low-priority information that might not be important to the user.

AlertMedium AlertMedium AlertMedium AlertMedium 134217728

The important information that does not need to be conveyed to the user immediately. For example, when a battery-level indicator is starting to reach a low level, it could generate a medium-level alert. Blind access utilities could then generate a sound to let the user know that important information is available, without actually interrupting the user's work. Users can then query the alert information any time they choose.

Animated Animated Animated Animated 16384

The object that rapidly or constantly changes appearance. Graphics that are occasionally animated, but not always, should be defined as GraphicORAnimated. This state should not be used to indicate that the object's location is changing.

Busy Busy Busy Busy 2048

A control that cannot accept input in its current condition.

Checked Checked Checked Checked 16

An object with a selected check box.

Collapsed Collapsed Collapsed Collapsed 1024

The hidden children of the object that are items in an outline or tree structure.

Default Default Default Default 256

The default button or menu item.

Expanded Expanded Expanded Expanded 512

The displayed children of the object that are items in an outline or tree structure.

ExtSelectable ExtSelectable ExtSelectable ExtSelectable 33554432

The altered selection such that all objects between the selection anchor, which is the object with the keyboard focus, and this object take on the anchor object's selection state. If the anchor object is not selected, the objects are removed from the selection. If the anchor object is selected, the selection is extended to include this object and all objects in between. You can set the selection state by combining this with AddSelection or RemoveSelection. This state does not change the focus or the selection anchor unless it is combined with TakeFocus.

Floating Floating Floating Floating 4096

The object that is not fixed to the boundary of its parent object and that does not move automatically along with the parent.

Focusable Focusable Focusable Focusable 1048576

The object on the active window that can receive keyboard focus.

Focused Focused Focused Focused 4

An object with the keyboard focus.

HasPopup HasPopup HasPopup HasPopup 1073741824

The object displays a pop-up menu or window when invoked.

HotTracked HotTracked HotTracked HotTracked 128

The object hot-tracked by the mouse, meaning its appearance is highlighted to indicate the mouse pointer is located over it.

Indeterminate Indeterminate Indeterminate Indeterminate 32

A three-state check box or toolbar button whose state is indeterminate. The check box is neither checked nor unchecked, and it is in the third or mixed state.

Invisible Invisible Invisible Invisible 32768

An object without a visible user interface.

Linked Linked Linked Linked 4194304

A linked object that has not been previously selected.

Marqueed Marqueed Marqueed Marqueed 8192

An object with scrolling or moving text or graphics.

Mixed Mixed Mixed Mixed 32

A three-state check box or toolbar button whose state is indeterminate. The check box is neither checked nor unchecked, and it is in the third or mixed state.

Moveable Moveable Moveable Moveable 262144

A movable object.

MultiSelectable MultiSelectable MultiSelectable MultiSelectable 16777216

An object that accepts multiple selected items.

None None None None 0

No state.

Offscreen Offscreen Offscreen Offscreen 65536

No on-screen representation. A sound or alert object would have this state, or a hidden window that is never made visible.

Pressed Pressed Pressed Pressed 8

A pressed object.

Protected Protected Protected Protected 536870912

A password-protected edit control.

ReadOnly ReadOnly ReadOnly ReadOnly 64

A read-only object.

Selectable Selectable Selectable Selectable 2097152

An object that can accept selection.

Selected Selected Selected Selected 2

A selected object.

SelfVoicing SelfVoicing SelfVoicing SelfVoicing 524288

The object or child can use text-to-speech (TTS) to describe itself. A speech-based accessibility aid should not announce information when an object with this state has the focus, because the object automatically announces information about itself.

Sizeable Sizeable Sizeable Sizeable 131072

A sizable object.

Traversed Traversed Traversed Traversed 8388608

A linked object that has previously been selected.

Unavailable Unavailable Unavailable Unavailable 1

An unavailable object.

Valid Valid Valid Valid 1073741823

A valid object. This property is deprecated in .NET Framework 2.0.

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. Because the chart legend is not an actual control based on Control, but instead is drawn by the chart control, it does not contain 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 using the AccessibleStates enumeration with the State property. See the AccessibleObject class overview for the complete code example.

// Inner class ChartControlAccessibleObject represents accessible information associated with the ChartControl.
// The ChartControlAccessibleObject is returned in the ChartControl::CreateAccessibilityInstance .
ref class ChartControlAccessibleObject: public ControlAccessibleObject
{
private:
   ChartControl^ chartControl;

public:
   ChartControlAccessibleObject( ChartControl^ ctrl )
      : ControlAccessibleObject( ctrl )
   {
      chartControl = ctrl;
   }


   property System::Windows::Forms::AccessibleRole Role 
   {

      // Gets the role for the Chart. This is used by accessibility programs.
      virtual System::Windows::Forms::AccessibleRole get() override
      {
         return ::AccessibleRole::Chart;
      }

   }

   property AccessibleStates State 
   {

      // Gets the state for the Chart. This is used by accessibility programs.
      virtual AccessibleStates get() override
      {
         return AccessibleStates::ReadOnly;
      }

   }

   // The CurveLegend objects are "child" controls in terms of accessibility so
   // return the number of ChartLengend objects.
   virtual int GetChildCount() override
   {
      return chartControl->Legends->Length;
   }


   // Gets the Accessibility object of the child CurveLegend idetified by index.
   virtual AccessibleObject^ GetChild( int index ) override
   {
      if ( index >= 0 && index < chartControl->Legends->Length )
      {
         return chartControl->Legends[ index ]->AccessibilityObject;
      }

      return nullptr;
   }


internal:

   // Helper function that is used by the CurveLegend's accessibility object
   // to navigate between sibiling controls. Specifically, this function is used in
   // the CurveLegend::CurveLegendAccessibleObject.Navigate function.
   AccessibleObject^ NavigateFromChild( CurveLegend::CurveLegendAccessibleObject^ child, AccessibleNavigation navdir )
   {
      switch ( navdir )
      {
         case AccessibleNavigation::Down:
         case AccessibleNavigation::Next:
            return GetChild( child->ID + 1 );

         case AccessibleNavigation::Up:
         case AccessibleNavigation::Previous:
            return GetChild( child->ID - 1 );
      }
      return nullptr;
   }


   // Helper function that is used by the CurveLegend's accessibility object
   // to select a specific CurveLegend control. Specifically, this function is used
   // in the CurveLegend::CurveLegendAccessibleObject.Select function.
   void SelectChild( CurveLegend::CurveLegendAccessibleObject^ child, AccessibleSelection selection )
   {
      int childID = child->ID;
      
      // Determine which selection action should occur, based on the
      // AccessibleSelection value.
      if ( (selection & AccessibleSelection::TakeSelection) != (AccessibleSelection)0 )
      {
         for ( int i = 0; i < chartControl->Legends->Length; i++ )
         {
            if ( i == childID )
            {
               chartControl->Legends[ i ]->Selected = true;
            }
            else
            {
               chartControl->Legends[ i ]->Selected = false;
            }

         }
         
         // AccessibleSelection->AddSelection means that the CurveLegend will be selected.
         if ( (selection & AccessibleSelection::AddSelection) != (AccessibleSelection)0 )
         {
            chartControl->Legends[ childID ]->Selected = true;
         }
         
         // AccessibleSelection->AddSelection means that the CurveLegend will be unselected.
         if ( (selection & AccessibleSelection::RemoveSelection) != (AccessibleSelection)0 )
         {
            chartControl->Legends[ childID ]->Selected = false;
         }
      }
   }

};

// class ChartControlAccessibleObject
// Inner class ChartControlAccessibleObject represents accessible information associated with the ChartControl.
// The ChartControlAccessibleObject is returned in the ChartControl.CreateAccessibilityInstance override.
public class ChartControlAccessibleObject : ControlAccessibleObject
{
    ChartControl chartControl;

    public ChartControlAccessibleObject(ChartControl ctrl) : base(ctrl) 
    {
        chartControl = ctrl;
    }

    // Gets the role for the Chart. This is used by accessibility programs.
    public override AccessibleRole Role
    {  
        get {
            return AccessibleRole.Chart;
        }
    }

    // Gets the state for the Chart. This is used by accessibility programs.
    public override AccessibleStates State
    {  
        get {                    
            return AccessibleStates.ReadOnly;
        }
    }

    // The CurveLegend objects are "child" controls in terms of accessibility so 
    // return the number of ChartLengend objects.
    public override int GetChildCount()
    {  
        return chartControl.Legends.Length;
    }

    // Gets the Accessibility object of the child CurveLegend idetified by index.
    public override AccessibleObject GetChild(int index)
    {  
        if (index >= 0 && index < chartControl.Legends.Length) {
            return chartControl.Legends[index].AccessibilityObject;
        }                
        return null;
    }

    // Helper function that is used by the CurveLegend's accessibility object
    // to navigate between sibiling controls. Specifically, this function is used in
    // the CurveLegend.CurveLegendAccessibleObject.Navigate function.
    internal AccessibleObject NavigateFromChild(CurveLegend.CurveLegendAccessibleObject child, 
                                                AccessibleNavigation navdir) 
    {  
        switch(navdir) {
            case AccessibleNavigation.Down:
            case AccessibleNavigation.Next:
                return GetChild(child.ID + 1);
                
            case AccessibleNavigation.Up:
            case AccessibleNavigation.Previous:
                return GetChild(child.ID - 1);                        
        }
        return null;
    }

    // Helper function that is used by the CurveLegend's accessibility object
    // to select a specific CurveLegend control. Specifically, this function is used
    // in the CurveLegend.CurveLegendAccessibleObject.Select function.
    internal void SelectChild(CurveLegend.CurveLegendAccessibleObject child, AccessibleSelection selection) 
    {   
        int childID = child.ID;

        // Determine which selection action should occur, based on the
        // AccessibleSelection value.
        if ((selection & AccessibleSelection.TakeSelection) != 0) {
            for(int i = 0; i < chartControl.Legends.Length; i++) {
                if (i == childID) {
                    chartControl.Legends[i].Selected = true;                        
                } else {
                    chartControl.Legends[i].Selected = false;
                }
            }

            // AccessibleSelection.AddSelection means that the CurveLegend will be selected.
            if ((selection & AccessibleSelection.AddSelection) != 0) {
                chartControl.Legends[childID].Selected = true;                        
            }

            // AccessibleSelection.AddSelection means that the CurveLegend will be unselected.
            if ((selection & AccessibleSelection.RemoveSelection) != 0) {
                chartControl.Legends[childID].Selected = false;                        
            }
        }            
    }
}
' Inner Class ChartControlAccessibleObject represents accessible information 
' associated with the ChartControl.
' The ChartControlAccessibleObject is returned in the         ' ChartControl.CreateAccessibilityInstance override.
Public Class ChartControlAccessibleObject
    Inherits Control.ControlAccessibleObject

    Private chartControl As ChartControl
    
    Public Sub New(ctrl As ChartControl)
        MyBase.New(ctrl)
        chartControl = ctrl
    End Sub 'New
    
    ' Get the role for the Chart. This is used by accessibility programs.            
    Public Overrides ReadOnly Property Role() As AccessibleRole
        Get
            Return System.Windows.Forms.AccessibleRole.Chart
        End Get
    End Property
    
    ' Get the state for the Chart. This is used by accessibility programs.            
    Public Overrides ReadOnly Property State() As AccessibleStates
        Get
            Return AccessibleStates.ReadOnly
        End Get
    End Property                        
    
    ' The CurveLegend objects are "child" controls in terms of accessibility so 
    ' return the number of ChartLengend objects.            
    Public Overrides Function GetChildCount() As Integer
        Return chartControl.Legends.Length
    End Function 
    
    ' Get the Accessibility object of the child CurveLegend idetified by index.
    Public Overrides Function GetChild(index As Integer) As AccessibleObject
        If index >= 0 And index < chartControl.Legends.Length Then
            Return chartControl.Legends(index).AccessibilityObject
        End If
        Return Nothing
    End Function 
    
    ' Helper function that is used by the CurveLegend's accessibility object
    ' to navigate between sibiling controls. Specifically, this function is used in
    ' the CurveLegend.CurveLegendAccessibleObject.Navigate function.
    Friend Function NavigateFromChild(child As CurveLegend.CurveLegendAccessibleObject, _
                                    navdir As AccessibleNavigation) As AccessibleObject
        Select Case navdir
            Case AccessibleNavigation.Down, AccessibleNavigation.Next
                    Return GetChild(child.ID + 1)
            
            Case AccessibleNavigation.Up, AccessibleNavigation.Previous
                    Return GetChild(child.ID - 1)
        End Select
        Return Nothing
    End Function            

    ' Helper function that is used by the CurveLegend's accessibility object
    ' to select a specific CurveLegend control. Specifically, this function is used 
    ' in the CurveLegend.CurveLegendAccessibleObject.Select function.            
    Friend Sub SelectChild(child As CurveLegend.CurveLegendAccessibleObject, selection As AccessibleSelection)
        Dim childID As Integer = child.ID
        
        ' Determine which selection action should occur, based on the
        ' AccessibleSelection value.
        If (selection And AccessibleSelection.TakeSelection) <> 0 Then
            Dim i As Integer
            For i = 0 To chartControl.Legends.Length - 1
                If i = childID Then
                    chartControl.Legends(i).Selected = True
                Else
                    chartControl.Legends(i).Selected = False
                End If
            Next i
            
            ' AccessibleSelection.AddSelection means that the CurveLegend will be selected.
            If (selection And AccessibleSelection.AddSelection) <> 0 Then
                chartControl.Legends(childID).Selected = True
            End If

            ' AccessibleSelection.AddSelection means that the CurveLegend will be unselected.                    
            If (selection And AccessibleSelection.RemoveSelection) <> 0 Then
                chartControl.Legends(childID).Selected = False
            End If
        End If
    End Sub 'SelectChild
End Class 'ChartControlAccessibleObject

Remarks

An accessible object can be associated with one or more of these states.

For more information about the accessibility application, see "Microsoft Active Accessibility" in the Microsoft Developer Network (MSDN) library at http://msdn.microsoft.com/library.

Applies to

See also