AccessibleObject.Role Propiedad
Definición
Importante
Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.
Obtiene la función de este objeto accesible.
public:
virtual property System::Windows::Forms::AccessibleRole Role { System::Windows::Forms::AccessibleRole get(); };
public virtual System.Windows.Forms.AccessibleRole Role { get; }
member this.Role : System.Windows.Forms.AccessibleRole
Public Overridable ReadOnly Property Role As AccessibleRole
Valor de propiedad
Uno de los valores de AccessibleRole o None si no se ha especificado ninguna función.
Ejemplos
En el ejemplo siguiente se muestra la creación de un control de gráfico compatible con accesibilidad, mediante las AccessibleObject clases y Control.ControlAccessibleObject para exponer información accesible. El control traza dos curvas junto con una leyenda. La ChartControlAccessibleObject
clase , que deriva de ControlAccessibleObject
, se usa en el CreateAccessibilityInstance método para proporcionar información accesible personalizada para el control de gráfico. Puesto que la leyenda del gráfico no es un control basado en real Control , sino que se dibuja mediante el control de gráfico, no tiene ninguna información accesible integrada. Por este motivo, la ChartControlAccessibleObject
clase invalida el GetChild método para devolver que CurveLegendAccessibleObject
representa información accesible para cada parte de la leyenda. Cuando una aplicación con reconocimiento accesible usa este control, el control puede proporcionar la información accesible necesaria.
Este fragmento de código muestra cómo invalidar la Role propiedad . Consulte la información general de la AccessibleObject clase para obtener el ejemplo de código completo.
// 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
' 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
End Class
Comentarios
El rol del objeto ayuda a describir la función del objeto.
Notas a los desarrolladores de herederos
Todos los objetos deben admitir esta propiedad.