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.
[Visual Basic] <Flags> <Serializable> Public Enum AccessibleStates [C#] [Flags] [Serializable] public enum AccessibleStates [C++] [Flags] [Serializable] __value public enum AccessibleStates [JScript] public Flags Serializable enum AccessibleStates
Remarks
An accessible object can be associated with one or more of these states.
For additional information on the accessibility application, search for "Microsoft Active Accessibility" in the Microsoft Developer Network (MSDN) library.
Members
| Member name | Description | Value |
|---|---|---|
| AlertHigh | 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. | 268435456 |
| AlertLow | The low-priority information that might not be important to the user. | 67108864 |
| AlertMedium | 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 at their leisure. | 134217728 |
| Animated | The 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. | 16384 |
| Busy | A control that cannot accept input in its current condition. | 2048 |
| Checked | An object with a selected check box. | 16 |
| Collapsed | The hidden children of the object that are items in an outline or tree structure. | 1024 |
| Default | The default button or menu item. | 256 |
| Expanded | The displayed children of the object that are items in an outline or tree structure. | 512 |
| ExtSelectable | 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 AccessibleSelection.AddSelection or AccessibleSelection.RemoveSelection. This state does not change the focus or the selection anchor unless it is combined with AccessibleSelection.TakeFocus. | 33554432 |
| Floating | The object that is not fixed to the boundary of its parent object and that does not move automatically along with the parent. | 4096 |
| Focusable | The object on the active window that can receive keyboard focus. | 1048576 |
| Focused | An object with the keyboard focus. | 4 |
| HotTracked | The object hot-tracked by the mouse, meaning its appearance is highlighted to indicate the mouse pointer is located over it. | 128 |
| Indeterminate | 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. | 32 |
| Invisible | An object without a visible user interface. | 32768 |
| Linked | A linked object that has not been previously selected. | 4194304 |
| Marqueed | An object with scrolling or moving text or graphics. | 8192 |
| Mixed | 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. | 32 |
| Moveable | A movable object. | 262144 |
| MultiSelectable | An object that accepts multiple selected items. | 16777216 |
| None | No state. | 0 |
| Offscreen | No on-screen representation. A sound or alert object would have this state, or a hidden window that is never made visible. | 65536 |
| Pressed | A pressed object. | 8 |
| Protected | A password-protected edit control. | 536870912 |
| ReadOnly | A read-only object. | 64 |
| Selectable | An object that can accept selection. | 2097152 |
| Selected | A selected object. | 2 |
| SelfVoicing | 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. | 524288 |
| Sizeable | A sizable object. | 131072 |
| Traversed | A linked object that has previously been selected. | 8388608 |
| Unavailable | An unavailable object. | 1 |
| Valid | A valid object. | 1073741823 |
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 using the AccessibleStates enumeration with the State property. See the AccessibleObject class overview for the complete code example.
[Visual Basic] ' 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 [C#] // 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; } } } } [C++] // Inner class ChartControlAccessibleObject represents accessible information associated with the ChartControl. // The ChartControlAccessibleObject is returned in the ChartControl::CreateAccessibilityInstance . __gc class ChartControlAccessibleObject : public ControlAccessibleObject { ChartControl* chartControl; public: ChartControlAccessibleObject(ChartControl* ctrl) : ControlAccessibleObject (ctrl) { chartControl = ctrl; } // Gets the role for the Chart. This is used by accessibility programs. __property System::Windows::Forms::AccessibleRole get_Role() { return AccessibleRole::Chart; } // Gets the state for the Chart. This is used by accessibility programs. __property AccessibleStates get_State() { return AccessibleStates::ReadOnly; } // The CurveLegend objects are "child" controls in terms of accessibility so // return the number of ChartLengend objects. int GetChildCount() { return chartControl->Legends->Length; } // Gets the Accessibility object of the child CurveLegend idetified by index. AccessibleObject* GetChild(int index) { if (index >= 0 && index < chartControl->Legends->Length) { return chartControl->Legends[index]->AccessibilityObject; } return 0; } // 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. public private: 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 0; } // 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) != 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; } } } }; // class ChartControlAccessibleObject
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Requirements
Namespace: System.Windows.Forms
Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
See Also
System.Windows.Forms Namespace | AccessibleEvents | AccessibleObject | AccessibleNavigation | AccessibleRole | AccessibleSelection