AccessibleStates Enumeration

Specifies values representing possible states for an accessible object.

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

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

'Declaration
<FlagsAttribute> _
Public Enumeration AccessibleStates
'Usage
Dim instance As AccessibleStates

/** @attribute FlagsAttribute() */ 
public enum AccessibleStates
FlagsAttribute 
public enum AccessibleStates

 Member nameDescription
AlertHighThe 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. 
AlertLowThe low-priority information that might not be important to the user. 
AlertMediumThe 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. 
AnimatedThe 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. 
BusyA control that cannot accept input in its current condition. 
CheckedAn object with a selected check box. 
CollapsedThe hidden children of the object that are items in an outline or tree structure. 
DefaultThe default button or menu item. 
ExpandedThe displayed children of the object that are items in an outline or tree structure. 
ExtSelectableThe 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 AccessibleSelection.AddSelection or AccessibleSelection.RemoveSelection. This state does not change the focus or the selection anchor unless it is combined with AccessibleSelection.TakeFocus
FloatingThe object that is not fixed to the boundary of its parent object and that does not move automatically along with the parent. 
FocusableThe object on the active window that can receive keyboard focus. 
FocusedAn object with the keyboard focus. 
HasPopup 
HotTrackedThe object hot-tracked by the mouse, meaning its appearance is highlighted to indicate the mouse pointer is located over it. 
IndeterminateA 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. 
InvisibleAn object without a visible user interface. 
LinkedA linked object that has not been previously selected. 
MarqueedAn object with scrolling or moving text or graphics. 
MixedA 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. 
MoveableA movable object. 
MultiSelectableAn object that accepts multiple selected items. 
NoneNo state. 
OffscreenNo on-screen representation. A sound or alert object would have this state, or a hidden window that is never made visible. 
PressedA pressed object. 
ProtectedA password-protected edit control. 
ReadOnlyA read-only object. 
SelectableAn object that can accept selection. 
SelectedA selected object. 
SelfVoicingThe 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. 
SizeableA sizable object. 
TraversedA linked object that has previously been selected. 
UnavailableAn unavailable object. 
ValidA valid object. 

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.

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 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

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

    public ChartControlAccessibleObject(ChartControl ctrl)
    {
        super(ctrl);
        chartControl = ctrl;
    } //ChartControlAccessibleObject

    // Gets the role for the Chart. This is used by accessibility programs.
    /** @property 
     */
    public AccessibleRole get_Role()
    {
        return AccessibleRole.Chart;
    } //get_Role

    // Gets the state for the Chart. This is used by accessibility programs.
    /** @property 
     */
    public AccessibleStates get_State()
    {
        return AccessibleStates.ReadOnly;
    } //get_State

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

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

    // 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)
    {
        if (navDir.Equals(AccessibleNavigation.Down) 
            || navDir.Equals(AccessibleNavigation.Next)) {
            return GetChild(child.get_ID() + 1);
        }
        else {
            if (navDir.Equals(AccessibleNavigation.Up) 
                || navDir.Equals(AccessibleNavigation.Previous)) {
                return GetChild(child.get_ID() - 1);
            }
        }
        return null;
    } //NavigateFromChild

    // 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.
    public void SelectChild(CurveLegend.CurveLegendAccessibleObject child, 
        AccessibleSelection selection)
    {
        int childID = child.get_ID();

        // Determine which selection action should occur, based on the
        // AccessibleSelection value.
        if (Convert.ToInt32(selection & AccessibleSelection.TakeSelection)
            != 0) {
            for (int i = 0; i < chartControl.get_Legends().get_Length(); 
                i++) {
                if (i == childID) {
                    ((CurveLegend)chartControl.get_Legends().get_Item(i)).
                        set_Selected(true);
                }
                else {
                    ((CurveLegend)chartControl.get_Legends().get_Item(i)).
                        set_Selected(false);
                }
            }

            // AccessibleSelection.AddSelection means that the CurveLegend 
            // will be selected.
            if (Convert.ToInt32(selection & AccessibleSelection.AddSelection)
                != 0) {
                ((CurveLegend)chartControl.get_Legends().get_Item(childID)).
                    set_Selected(true);
            }

            // AccessibleSelection.AddSelection means that the CurveLegend 
            // will be unselected.
            if (Convert.ToInt32(selection & 
                AccessibleSelection.RemoveSelection) != 0) {
                ((CurveLegend)chartControl.get_Legends().get_Item(childID)).
                    set_Selected(false);
            }
        }
    } //SelectChild
} //ChartControlAccessibleObject

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

Community Additions

ADD
Show: