AccessibleObject.Navigate(AccessibleNavigation) Método
Definição
Importante
Algumas informações se referem a produtos de pré-lançamento que podem ser substancialmente modificados antes do lançamento. A Microsoft não oferece garantias, expressas ou implícitas, das informações aqui fornecidas.
Navega para outro objeto acessível.
public:
virtual System::Windows::Forms::AccessibleObject ^ Navigate(System::Windows::Forms::AccessibleNavigation navdir);
public virtual System.Windows.Forms.AccessibleObject Navigate (System.Windows.Forms.AccessibleNavigation navdir);
public virtual System.Windows.Forms.AccessibleObject? Navigate (System.Windows.Forms.AccessibleNavigation navdir);
abstract member Navigate : System.Windows.Forms.AccessibleNavigation -> System.Windows.Forms.AccessibleObject
override this.Navigate : System.Windows.Forms.AccessibleNavigation -> System.Windows.Forms.AccessibleObject
Public Overridable Function Navigate (navdir As AccessibleNavigation) As AccessibleObject
Parâmetros
- navdir
- AccessibleNavigation
Um dos valores de AccessibleNavigation.
Retornos
Um AccessibleObject que representa um dos valores de AccessibleNavigation.
Exceções
A tentativa de navegação falha.
Exemplos
O exemplo a seguir demonstra a criação de um controle de gráfico com reconhecimento de acessibilidade, usando o e Control.ControlAccessibleObject as AccessibleObject classes para expor informações acessíveis. O controle plota duas curvas junto com uma legenda. A ChartControlAccessibleObject
classe, que deriva de ControlAccessibleObject
, é usada no CreateAccessibilityInstance método para fornecer informações acessíveis personalizadas para o controle do gráfico. Como a legenda do gráfico não é um controle baseado em real Control , mas é desenhada pelo controle do gráfico, ela não tem nenhuma informação acessível interna. Por isso, a ChartControlAccessibleObject
classe substitui o GetChild método para retornar o CurveLegendAccessibleObject
que representa informações acessíveis para cada parte da legenda. Quando um aplicativo com reconhecimento acessível usa esse controle, o controle pode fornecer as informações acessíveis necessárias.
Esse código demonstra a substituição do Navigate método. Confira a visão geral da AccessibleObject classe para o exemplo de código 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
Comentários
A navegação, espacial e lógica, é sempre restrita aos elementos da interface do usuário dentro de um contêiner. Com a navegação espacial, os clientes podem navegar apenas para um irmão do objeto inicial. Dependendo do sinalizador de navegação usado com navegação lógica, os clientes podem navegar até uma criança ou para um irmão do objeto inicial. Esse método não altera a seleção nem o foco. Para alterar o foco ou selecionar um objeto, use Select. O Navigate método recupera apenas elementos de interface do usuário que têm um local de tela definido.
Notas aos Herdeiros
Todos os objetos visuais devem dar suporte a esse método. Se um objeto tiver o estado Invisible, a navegação para esse objeto oculto poderá falhar. Alguns elementos de interface definidos pelo sistema, como menus, itens de menu e menus pop-up, permitem a navegação para objetos que não estão visíveis. No entanto, outros elementos de interface do usuário definidos pelo sistema não dão suporte a isso. Se possível, os servidores devem dar suporte à navegação para objetos que não estão visíveis, mas esse suporte não é necessário e os clientes não devem esperar por isso.