AccessibleObject.State Właściwość
Definicja
Ważne
Niektóre informacje odnoszą się do produktu w wersji wstępnej, który może zostać znacząco zmodyfikowany przed wydaniem. Firma Microsoft nie udziela żadnych gwarancji, jawnych lub domniemanych, w odniesieniu do informacji podanych w tym miejscu.
Pobiera stan tego dostępnego obiektu.
public:
virtual property System::Windows::Forms::AccessibleStates State { System::Windows::Forms::AccessibleStates get(); };public virtual System.Windows.Forms.AccessibleStates State { get; }member this.State : System.Windows.Forms.AccessibleStatesPublic Overridable ReadOnly Property State As AccessibleStatesWartość właściwości
AccessibleStates Jedna z wartości lub None, jeśli nie ustawiono żadnego stanu.
Przykłady
W poniższym przykładzie pokazano tworzenie kontrolki wykresu obsługującego ułatwienia dostępu przy użyciu AccessibleObject klas i Control.ControlAccessibleObject w celu uwidocznienia dostępnych informacji. Kontrolka kreśli dwie krzywe wraz z legendą. Klasa ChartControlAccessibleObject , która pochodzi z ControlAccessibleObjectklasy , jest używana w metodzie CreateAccessibilityInstance w celu udostępnienia niestandardowych informacji dostępnych dla kontrolki wykresu. Ponieważ legenda wykresu nie jest rzeczywistą Control kontrolką opartą na wykresie, ale zamiast tego jest rysowana przez kontrolkę wykresu, nie ma żadnych wbudowanych informacji dostępnych. W związku z tym ChartControlAccessibleObject klasa zastępuje metodę GetChild , aby zwrócić CurveLegendAccessibleObject informacje, które reprezentują dostępne informacje dla każdej części legendy. Gdy aplikacja z obsługą dostępu korzysta z tej kontrolki, kontrolka może dostarczyć niezbędne informacje dostępne.
Ten fragment kodu pokazuje zastępowanie State właściwości. Zobacz omówienie klasy, aby zapoznać się z AccessibleObject kompletnym przykładem kodu.
// 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
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