AccessibleObject.Bounds Proprietà
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Ottiene la posizione e le dimensioni dell'oggetto accessibile.
public:
virtual property System::Drawing::Rectangle Bounds { System::Drawing::Rectangle get(); };public virtual System.Drawing.Rectangle Bounds { get; }member this.Bounds : System.Drawing.RectanglePublic Overridable ReadOnly Property Bounds As RectangleValore della proprietà
Oggetto Rectangle che rappresenta i limiti dell'oggetto accessibile.
Eccezioni
Non è possibile recuperare i limiti del controllo.
Esempio
Nell'esempio seguente viene illustrata la creazione di un controllo grafico compatibile con l'accessibilità, usando le AccessibleObject classi e Control.ControlAccessibleObject per esporre informazioni accessibili. Il controllo traccia due curve insieme a una legenda. La ChartControlAccessibleObject classe , che deriva da ControlAccessibleObject, viene utilizzata nel CreateAccessibilityInstance metodo per fornire informazioni personalizzate accessibili per il controllo grafico. Poiché la legenda del grafico non è un controllo effettivo Control basato su , ma viene invece disegnato dal controllo grafico, non dispone di informazioni accessibili predefinite. Per questo motivo, la ChartControlAccessibleObject classe esegue l'override del GetChild metodo per restituire l'oggetto CurveLegendAccessibleObject che rappresenta informazioni accessibili per ogni parte della legenda. Quando un'applicazione con riconoscimento dell'accesso usa questo controllo, il controllo può fornire le informazioni accessibili necessarie.
Questo estratto di codice illustra l'override della Bounds proprietà . Vedere la panoramica della AccessibleObject classe per l'esempio di codice completo.
// Inner class CurveLegendAccessibleObject represents accessible information
// associated with the CurveLegend object.
public:
ref class CurveLegendAccessibleObject: public AccessibleObject
{
private:
CurveLegend^ curveLegend;
public:
CurveLegendAccessibleObject( CurveLegend^ curveLegend )
: AccessibleObject()
{
this->curveLegend = curveLegend;
}
private:
property ChartControlAccessibleObject^ ChartControl
{
// Private property that helps get the reference to the parent ChartControl.
ChartControlAccessibleObject^ get()
{
return dynamic_cast<ChartControlAccessibleObject^>(Parent);
}
}
internal:
property int ID
{
// Internal helper function that returns the ID for this CurveLegend.
int get()
{
for ( int i = 0; i < ChartControl->GetChildCount(); i++ )
{
if ( ChartControl->GetChild( i ) == this )
{
return i;
}
}
return -1;
}
}
public:
property Rectangle Bounds
{
// Gets the Bounds for the CurveLegend. This is used by accessibility programs.
virtual Rectangle get() override
{
// The bounds is in screen coordinates.
Point loc = curveLegend->Location;
return Rectangle(curveLegend->chart->PointToScreen( loc ),curveLegend->Size);
}
}
property String^ Name
{
// Gets or sets the Name for the CurveLegend. This is used by accessibility programs.
virtual String^ get() override
{
return curveLegend->Name;
}
virtual void set( String^ value ) override
{
curveLegend->Name = value;
}
}
property AccessibleObject^ Parent
{
// Gets the Curve Legend Parent's Accessible object.
// This is used by accessibility programs.
virtual AccessibleObject^ get() override
{
return curveLegend->chart->AccessibilityObject;
}
}
property System::Windows::Forms::AccessibleRole Role
{
// Gets the role for the CurveLegend. This is used by accessibility programs.
virtual System::Windows::Forms::AccessibleRole get() override
{
return ::AccessibleRole::StaticText;
}
}
property AccessibleStates State
{
// Gets the state based on the selection for the CurveLegend.
// This is used by accessibility programs.
virtual AccessibleStates get() override
{
AccessibleStates state = AccessibleStates::Selectable;
if ( curveLegend->Selected )
{
state = static_cast<AccessibleStates>(state | AccessibleStates::Selected);
}
return state;
}
}
// Navigates through siblings of this CurveLegend. This is used by accessibility programs.
virtual AccessibleObject^ Navigate( AccessibleNavigation navdir ) override
{
// Uses the internal NavigateFromChild helper function that exists
// on ChartControlAccessibleObject.
return ChartControl->NavigateFromChild( this, navdir );
}
// Selects or unselects this CurveLegend. This is used by accessibility programs.
virtual void Select( AccessibleSelection selection ) override
{
// Uses the internal SelectChild helper function that exists
// on ChartControlAccessibleObject.
ChartControl->SelectChild( this, selection );
}
};
// Inner class CurveLegendAccessibleObject represents accessible information
// associated with the CurveLegend object.
public class CurveLegendAccessibleObject : AccessibleObject
{
private CurveLegend curveLegend;
public CurveLegendAccessibleObject(CurveLegend curveLegend) : base()
{
this.curveLegend = curveLegend;
}
// Private property that helps get the reference to the parent ChartControl.
private ChartControlAccessibleObject ChartControl
{
get {
return Parent as ChartControlAccessibleObject;
}
}
// Internal helper function that returns the ID for this CurveLegend.
internal int ID
{
get {
for(int i = 0; i < ChartControl.GetChildCount(); i++) {
if (ChartControl.GetChild(i) == this) {
return i;
}
}
return -1;
}
}
// Gets the Bounds for the CurveLegend. This is used by accessibility programs.
public override Rectangle Bounds
{
get {
// The bounds is in screen coordinates.
Point loc = curveLegend.Location;
return new Rectangle(curveLegend.chart.PointToScreen(loc), curveLegend.Size);
}
}
// Gets or sets the Name for the CurveLegend. This is used by accessibility programs.
public override string Name
{
get {
return curveLegend.Name;
}
set {
curveLegend.Name = value;
}
}
// Gets the Curve Legend Parent's Accessible object.
// This is used by accessibility programs.
public override AccessibleObject Parent
{
get {
return curveLegend.chart.AccessibilityObject;
}
}
// Gets the role for the CurveLegend. This is used by accessibility programs.
public override AccessibleRole Role
{
get {
return AccessibleRole.StaticText;
}
}
// Gets the state based on the selection for the CurveLegend.
// This is used by accessibility programs.
public override AccessibleStates State
{
get {
AccessibleStates state = AccessibleStates.Selectable;
if (curveLegend.Selected)
{
state |= AccessibleStates.Selected;
}
return state;
}
}
// Navigates through siblings of this CurveLegend. This is used by accessibility programs.
public override AccessibleObject Navigate(AccessibleNavigation navdir)
{
// Uses the internal NavigateFromChild helper function that exists
// on ChartControlAccessibleObject.
return ChartControl.NavigateFromChild(this, navdir);
}
// Selects or unselects this CurveLegend. This is used by accessibility programs.
public override void Select(AccessibleSelection selection)
{
// Uses the internal SelectChild helper function that exists
// on ChartControlAccessibleObject.
ChartControl.SelectChild(this, selection);
}
}
' Inner class CurveLegendAccessibleObject represents accessible information
' associated with the CurveLegend object.
Public Class CurveLegendAccessibleObject
Inherits AccessibleObject
Private curveLegend As CurveLegend
Public Sub New(curveLegend As CurveLegend)
Me.curveLegend = curveLegend
End Sub
' Private property that helps get the reference to the parent ChartControl.
Private ReadOnly Property ChartControl() As ChartControlAccessibleObject
Get
Return CType(Parent, ChartControlAccessibleObject)
End Get
End Property
' Friend helper function that returns the ID for this CurveLegend.
Friend ReadOnly Property ID() As Integer
Get
Dim i As Integer
For i = 0 To (ChartControl.GetChildCount()) - 1
If ChartControl.GetChild(i) Is Me Then
Return i
End If
Next i
Return - 1
End Get
End Property
' Gets the Bounds for the CurveLegend. This is used by accessibility programs.
Public Overrides ReadOnly Property Bounds() As Rectangle
Get
' The bounds is in screen coordinates.
Dim loc As Point = curveLegend.Location
Return New Rectangle(curveLegend.chart.PointToScreen(loc), curveLegend.Size)
End Get
End Property
' Gets or sets the Name for the CurveLegend. This is used by accessibility programs.
Public Overrides Property Name() As String
Get
Return curveLegend.Name
End Get
Set
curveLegend.Name = value
End Set
End Property
' Gets the Curve Legend Parent's Accessible object.
' This is used by accessibility programs.
Public Overrides ReadOnly Property Parent() As AccessibleObject
Get
Return curveLegend.chart.AccessibilityObject
End Get
End Property
' Gets the role for the CurveLegend. This is used by accessibility programs.
Public Overrides ReadOnly Property Role() As AccessibleRole
Get
Return System.Windows.Forms.AccessibleRole.StaticText
End Get
End Property
' Gets the state based on the selection for the CurveLegend.
' This is used by accessibility programs.
Public Overrides ReadOnly Property State() As AccessibleStates
Get
Dim stateTemp As AccessibleStates = AccessibleStates.Selectable
If curveLegend.Selected Then
stateTemp = stateTemp Or AccessibleStates.Selected
End If
Return stateTemp
End Get
End Property
' Navigates through siblings of this CurveLegend. This is used by accessibility programs.
Public Overrides Function Navigate(navdir As AccessibleNavigation) As AccessibleObject
' Use the Friend NavigateFromChild helper function that exists
' on ChartControlAccessibleObject.
Return ChartControl.NavigateFromChild(Me, navdir)
End Function
' Selects or unselects this CurveLegend. This is used by accessibility programs.
Public Overrides Sub [Select](selection As AccessibleSelection)
' Use the internal SelectChild helper function that exists
' on ChartControlAccessibleObject.
ChartControl.SelectChild(Me, selection)
End Sub
End Class
Commenti
La Bounds proprietà recupera il rettangolo di delimitazione dell'oggetto nelle coordinate dello schermo. Se l'oggetto ha una forma nontangulare, questa proprietà rappresenta il rettangolo più piccolo che comprende completamente l'intera area dell'oggetto. Pertanto, per gli oggetti non rectangulari, ad esempio gli elementi della visualizzazione elenco, le coordinate del rettangolo di delimitazione dell'oggetto possono non riuscire, se testate, chiamando il HitTest metodo , perché HitTest determina i limiti dell'oggetto in base a pixel.
Note per gli eredi
L'implementazione predefinita restituisce il rettangolo di delimitazione dell'oggetto accessibile se l'oggetto esegue il wrapping di un controllo di sistema; in caso contrario, restituisce Empty. Tutti gli oggetti accessibili visibili devono supportare questo metodo. Gli oggetti audio non supportano questo metodo.
