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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)

[FlagsAttribute]
public enum AccessibleStates

Member nameDescription
NoneNo state.
UnavailableAn unavailable object.
SelectedA selected object.
FocusedAn object with the keyboard focus.
PressedA pressed object.
CheckedAn object with a selected check box.
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.
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.
ReadOnlyA read-only object.
HotTrackedThe object hot-tracked by the mouse, meaning its appearance is highlighted to indicate the mouse pointer is located over it.
DefaultThe default button or menu item.
ExpandedThe displayed children of the object that are items in an outline or tree structure.
CollapsedThe hidden children of the object that are items in an outline or tree structure.
BusyA control that cannot accept input in its current condition.
FloatingThe object that is not fixed to the boundary of its parent object and that does not move automatically along with the parent.
MarqueedAn object with scrolling or moving text or graphics.
AnimatedThe object that rapidly or constantly changes appearance. Graphics that are occasionally animated, but not always, should be defined as Graphic OR Animated. This state should not be used to indicate that the object's location is changing.
InvisibleAn object without a visible user interface.
OffscreenNo on-screen representation. A sound or alert object would have this state, or a hidden window that is never made visible.
SizeableA sizable object.
MoveableA movable 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.
FocusableThe object on the active window that can receive keyboard focus.
SelectableAn object that can accept selection.
LinkedA linked object that has not been previously selected.
TraversedA linked object that has previously been selected.
MultiSelectableAn object that accepts multiple selected items.
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.
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.
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.
ProtectedA password-protected edit control.
HasPopupThe object displays a pop-up menu or window when invoked.
Valid Obsolete. A valid object. This property is deprecated in .NET Framework 2.0.

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 : 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;                        
            }
        }            
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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