AccessibleObject.Parent 属性
获取辅助性对象的父级。
**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）
语法
声明
Public Overridable ReadOnly Property Parent As AccessibleObject
用法
Dim instance As AccessibleObject
Dim value As AccessibleObject
value = instance.Parent
public virtual AccessibleObject Parent { get; }
public:
virtual property AccessibleObject^ Parent {
AccessibleObject^ get ();
}
/** @property */
public AccessibleObject get_Parent ()
public function get Parent () : AccessibleObject
属性值
AccessibleObject，表示辅助性对象的父级，或者，如果没有父对象，则是 空引用（在 Visual Basic 中为 Nothing）。
备注
给继承者的说明 所有对象都应支持该属性。
示例
下面的示例演示了如何创建一个具有辅助功能的图表控件，并使用 AccessibleObject 和 Control.ControlAccessibleObject 类来公开辅助性信息。该控件绘制两条带有图例的曲线。CreateAccessibilityInstance 方法使用从 ControlAccessibleObject 派生的 ChartControlAccessibleObject 类，为图表控件提供自定义辅助性信息。因为图表图例不是实际的基于 Control 的控件，而是由图表控件绘制的，所以它不提供任何内置的辅助性信息。因此，ChartControlAccessibleObject 类重写 GetChild 方法以返回 CurveLegendAccessibleObject（表示该图例各部分的辅助性信息）。当具有辅助功能的应用程序使用该控件时，该控件能提供必需的辅助性信息。
这段代码摘录演示了如何重写 Parent 属性。有关完整的代码示例，请参见 AccessibleObject 类概述。
' 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 'New
' 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 'CurveLegendAccessibleObject
// 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:
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 static class CurveLegendAccessibleObject extends AccessibleObject
{
private CurveLegend curveLegend;
public CurveLegendAccessibleObject(CurveLegend curveLegend)
{
this.curveLegend = curveLegend;
} //CurveLegendAccessibleObject
// Private property that helps get the reference to the parent
// ChartControl.
/** @property
*/
private ChartControlAccessibleObject get_ChartControl()
{
return (ChartControlAccessibleObject)get_Parent();
} //get_ChartControl
// Internal helper function that returns the ID for this CurveLegend.
/** @property
*/
int get_ID()
{
for (int i = 0; i < get_ChartControl().GetChildCount(); i++) {
if (get_ChartControl().GetChild(i).Equals(this)) {
return i;
}
}
return -1;
} //get_ID
// Gets the Bounds for the CurveLegend.
// This is used by accessibility programs.
/** @property
*/
public Rectangle get_Bounds()
{
// The bounds is in screen coordinates.
Point loc = curveLegend.get_Location();
return new Rectangle(curveLegend.chart.PointToScreen(loc),
curveLegend.get_Size());
} //get_Bounds
// Gets or sets the Name for the CurveLegend.
// This is used by accessibility programs.
/** @property
*/
public String get_Name()
{
return curveLegend.get_Name();
} //get_Name
/** @property
*/
public void set_Name(String value)
{
curveLegend.set_Name(value);
} //set_Name
// Gets the Curve Legend Parent's Accessible object.
// This is used by accessibility programs.
/** @property
*/
public AccessibleObject get_Parent()
{
return curveLegend.chart.get_AccessibilityObject();
} //get_Parent
// Gets the role for the CurveLegend.
// This is used by accessibility programs.
/** @property
*/
public AccessibleRole get_Role()
{
return AccessibleRole.StaticText;
} //get_Role
// Gets the state based on the selection for the CurveLegend.
// This is used by accessibility programs.
/** @property
*/
public AccessibleStates get_State()
{
AccessibleStates state = AccessibleStates.Selectable;
if (curveLegend.get_Selected()) {
state = state | AccessibleStates.Selected;
}
return state;
} //get_State
// Navigates through siblings of this CurveLegend.
// This is used by accessibility programs.
public AccessibleObject Navigate(AccessibleNavigation navDir)
{
// Uses the internal NavigateFromChild helper function
// that exists on ChartControlAccessibleObject.
return get_ChartControl().NavigateFromChild(this, navDir);
} //Navigate
// Selects or unselects this CurveLegend.
// This is used by accessibility programs.
public void Select(AccessibleSelection selection)
{
// Uses the internal SelectChild helper function that exists
// on ChartControlAccessibleObject.
get_ChartControl().SelectChild(this, selection);
} //Select
} //CurveLegendAccessibleObject
平台
Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息
.NET Framework
受以下版本支持：2.0、1.1、1.0
请参见
参考
AccessibleObject 类
AccessibleObject 成员
System.Windows.Forms 命名空间
AccessibleObject.Bounds 属性
AccessibleObject.DefaultAction 属性
AccessibleObject.Description 属性
AccessibleObject.Help 属性
AccessibleObject.KeyboardShortcut 属性
AccessibleObject.Name 属性
Role
State
Value