共用方式為


AccessibleObject 類別

定義

提供資訊,讓協助工具應用程式能用於為殘障使用者調整應用程式的使用者介面 (UI)。

public ref class AccessibleObject : MarshalByRefObject, Accessibility::IAccessible, System::Reflection::IReflect
public ref class AccessibleObject : System::Runtime::InteropServices::StandardOleMarshalObject, Accessibility::IAccessible, System::Reflection::IReflect
[System.Runtime.InteropServices.ComVisible(true)]
public class AccessibleObject : MarshalByRefObject, Accessibility.IAccessible, System.Reflection.IReflect
[System.Runtime.InteropServices.ComVisible(true)]
public class AccessibleObject : System.Runtime.InteropServices.StandardOleMarshalObject, Accessibility.IAccessible, System.Reflection.IReflect
public class AccessibleObject : System.Runtime.InteropServices.StandardOleMarshalObject, Accessibility.IAccessible, System.Reflection.IReflect
[<System.Runtime.InteropServices.ComVisible(true)>]
type AccessibleObject = class
    inherit MarshalByRefObject
    interface IReflect
    interface IAccessible
    interface UnsafeNativeMethods.IEnumVariant
    interface UnsafeNativeMethods.IMarshal
[<System.Runtime.InteropServices.ComVisible(true)>]
type AccessibleObject = class
    inherit StandardOleMarshalObject
    interface IReflect
    interface IAccessible
    interface UnsafeNativeMethods.IEnumVariant
    interface UnsafeNativeMethods.IOleWindow
[<System.Runtime.InteropServices.ComVisible(true)>]
type AccessibleObject = class
    inherit StandardOleMarshalObject
    interface IReflect
    interface IAccessible
[<System.Runtime.InteropServices.ComVisible(true)>]
type AccessibleObject = class
    inherit StandardOleMarshalObject
    interface IReflect
    interface IAccessible
    interface UnsafeNativeMethods.IAccessibleEx
    interface UnsafeNativeMethods.IServiceProvider
    interface UnsafeNativeMethods.IRawElementProviderSimple
    interface UnsafeNativeMethods.IRawElementProviderFragment
    interface UnsafeNativeMethods.IRawElementProviderFragmentRoot
    interface UnsafeNativeMethods.IInvokeProvider
    interface UnsafeNativeMethods.IValueProvider
    interface UnsafeNativeMethods.IRangeValueProvider
    interface UnsafeNativeMethods.IExpandCollapseProvider
    interface UnsafeNativeMethods.IToggleProvider
    interface UnsafeNativeMethods.ITableProvider
    interface UnsafeNativeMethods.ITableItemProvider
    interface UnsafeNativeMethods.IGridProvider
    interface UnsafeNativeMethods.IGridItemProvider
    interface UnsafeNativeMethods.IEnumVariant
    interface UnsafeNativeMethods.IOleWindow
    interface UnsafeNativeMethods.ILegacyIAccessibleProvider
    interface UnsafeNativeMethods.ISelectionProvider
    interface UnsafeNativeMethods.ISelectionItemProvider
    interface UnsafeNativeMethods.IRawElementProviderHwndOverride
    interface UnsafeNativeMethods.IScrollItemProvider
type AccessibleObject = class
    inherit StandardOleMarshalObject
    interface IReflect
    interface IAccessible
    interface Interop.UiaCore.IAccessibleEx
    interface Interop.Ole32.IServiceProvider
    interface Interop.UiaCore.IRawElementProviderSimple
    interface Interop.UiaCore.IRawElementProviderFragment
    interface Interop.UiaCore.IRawElementProviderFragmentRoot
    interface Interop.UiaCore.IInvokeProvider
    interface Interop.UiaCore.IValueProvider
    interface Interop.UiaCore.IRangeValueProvider
    interface Interop.UiaCore.IExpandCollapseProvider
    interface Interop.UiaCore.IToggleProvider
    interface Interop.UiaCore.ITableProvider
    interface Interop.UiaCore.ITableItemProvider
    interface Interop.UiaCore.IGridProvider
    interface Interop.UiaCore.IGridItemProvider
    interface Interop.Oleaut32.IEnumVariant
    interface Interop.Ole32.IOleWindow
    interface Interop.UiaCore.ILegacyIAccessibleProvider
    interface Interop.UiaCore.ISelectionProvider
    interface Interop.UiaCore.ISelectionItemProvider
    interface Interop.UiaCore.IRawElementProviderHwndOverride
    interface Interop.UiaCore.IScrollItemProvider
    interface Interop.UiaCore.IMultipleViewProvider
    interface Interop.UiaCore.ITextProvider
    interface Interop.UiaCore.ITextProvider2
type AccessibleObject = class
    inherit StandardOleMarshalObject
    interface IReflect
    interface IAccessible
    interface Interop.UiaCore.IAccessibleEx
    interface IServiceProvider.Interface
    interface Interop.UiaCore.IRawElementProviderSimple
    interface Interop.UiaCore.IRawElementProviderFragment
    interface Interop.UiaCore.IRawElementProviderFragmentRoot
    interface Interop.UiaCore.IInvokeProvider
    interface Interop.UiaCore.IValueProvider
    interface Interop.UiaCore.IRangeValueProvider
    interface Interop.UiaCore.IExpandCollapseProvider
    interface Interop.UiaCore.IToggleProvider
    interface Interop.UiaCore.ITableProvider
    interface Interop.UiaCore.ITableItemProvider
    interface Interop.UiaCore.IGridProvider
    interface Interop.UiaCore.IGridItemProvider
    interface IEnumVARIANT.Interface
    interface IOleWindow.Interface
    interface Interop.UiaCore.ILegacyIAccessibleProvider
    interface Interop.UiaCore.ISelectionProvider
    interface Interop.UiaCore.ISelectionItemProvider
    interface Interop.UiaCore.IRawElementProviderHwndOverride
    interface Interop.UiaCore.IScrollItemProvider
    interface Interop.UiaCore.IMultipleViewProvider
    interface Interop.UiaCore.ITextProvider
    interface Interop.UiaCore.ITextProvider2
type AccessibleObject = class
    inherit StandardOleMarshalObject
    interface IReflect
    interface IAccessible.Interface
    interface IAccessible
    interface IAccessibleEx.Interface
    interface IServiceProvider.Interface
    interface IRawElementProviderSimple.Interface
    interface IRawElementProviderFragment.Interface
    interface IRawElementProviderFragmentRoot.Interface
    interface IInvokeProvider.Interface
    interface IValueProvider.Interface
    interface IRangeValueProvider.Interface
    interface IExpandCollapseProvider.Interface
    interface IToggleProvider.Interface
    interface ITableProvider.Interface
    interface ITableItemProvider.Interface
    interface IGridProvider.Interface
    interface IGridItemProvider.Interface
    interface IEnumVARIANT.Interface
    interface IOleWindow.Interface
    interface ILegacyIAccessibleProvider.Interface
    interface ISelectionProvider.Interface
    interface ISelectionItemProvider.Interface
    interface IRawElementProviderHwndOverride.Interface
    interface IScrollItemProvider.Interface
    interface IMultipleViewProvider.Interface
    interface ITextProvider.Interface
    interface ITextProvider2.Interface
    interface IDispatch.Interface
    interface IDispatchEx.Interface
Public Class AccessibleObject
Inherits MarshalByRefObject
Implements IAccessible, IReflect
Public Class AccessibleObject
Inherits StandardOleMarshalObject
Implements IAccessible, IReflect
繼承
AccessibleObject
繼承
衍生
屬性
實作

範例

下列程式碼範例示範如何使用 AccessibleObjectControl.ControlAccessibleObject 類別來公開無障礙資訊,建立協助工具感知圖表控制項。 控制項會繪製兩個曲線以及圖例。 ChartControlAccessibleObject衍生自 ControlAccessibleObject 的 類別會用於 方法中 CreateAccessibilityInstance ,以提供圖表控制項的自訂可存取訊號。 因為圖表圖例不是實際的 Control 控制項,而是由圖表控制項繪製,所以它沒有任何內建的可存取訊號。 因此,類別會 ChartControlAccessibleObjectGetChild 覆寫 方法,以傳回 CurveLegendAccessibleObject ,代表圖例每個部分的可存取訊號。 當可存取感知應用程式使用此控制項時,控制項可以提供必要的可存取訊號。

#using <Accessibility.dll>
#using <System.dll>
#using <System.Windows.Forms.dll>
#using <System.Drawing.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;

// Declare a chart control that demonstrates accessibility in Windows Forms.
public ref class ChartControl: public System::Windows::Forms::UserControl
{
public:
   ref class ChartControlAccessibleObject;

   // forward declaration
   // Inner Class that represents a legend for a curve in the chart.
   ref class CurveLegend
   {

      // 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 );
         }

      };


   private:

      // class CurveLgendAccessibleObject
      String^ name;
      ChartControl^ chart;
      CurveLegendAccessibleObject^ accObj;
      bool selected;
      Point location;

   public:
      CurveLegend( ChartControl^ chart, String^ name )
      {
         this->chart = chart;
         this->name = name;
         selected = true;
      }


      property AccessibleObject^ AccessibilityObject 
      {

         // Gets the accessibility object for the curve legend.
         AccessibleObject^ get()
         {
            if ( accObj == nullptr )
            {
               accObj = gcnew CurveLegendAccessibleObject( this );
            }

            return accObj;
         }

      }

      property Rectangle Bounds 
      {

         // Gets the bounds for the curve legend.
         Rectangle get()
         {
            return Rectangle(Location,Size);
         }

      }

      property Point Location 
      {

         // Gets or sets the location for the curve legend.
         Point get()
         {
            return location;
         }

         void set( Point value )
         {
            location = value;
            chart->Invalidate();
            
            // Notifies the chart of the location change. This is used for
            // the accessibility information. AccessibleEvents::LocationChange
            // tells the chart the reason for the notification.
            chart->AccessibilityNotifyClients( AccessibleEvents::LocationChange, (dynamic_cast<CurveLegendAccessibleObject^>(AccessibilityObject))->ID );
         }

      }

      property String^ Name 
      {

         // Gets or sets the Name for the curve legend.
         String^ get()
         {
            return name;
         }

         void set( String^ value )
         {
            if ( name != value )
            {
               name = value;
               chart->Invalidate();
               
               // Notifies the chart of the name change. This is used for
               // the accessibility information. AccessibleEvents::NameChange
               // tells the chart the reason for the notification.
               chart->AccessibilityNotifyClients( AccessibleEvents::NameChange, (dynamic_cast<CurveLegendAccessibleObject^>(AccessibilityObject))->ID );
            }
         }

      }

      property bool Selected 
      {

         // Gets or sets the Selected state for the curve legend.
         bool get()
         {
            return selected;
         }

         void set( bool value )
         {
            if ( selected != value )
            {
               selected = value;
               chart->Invalidate();
               
               // Notifies the chart of the selection value change. This is used for
               // the accessibility information. The AccessibleEvents value depends upon
               // if the selection is true (AccessibleEvents::SelectionAdd) or
               // false (AccessibleEvents::SelectionRemove).
               chart->AccessibilityNotifyClients( selected ? AccessibleEvents::SelectionAdd : AccessibleEvents::SelectionRemove, (dynamic_cast<CurveLegendAccessibleObject^>(AccessibilityObject))->ID );
            }
         }

      }

      property System::Drawing::Size Size 
      {

         // Gets the Size for the curve legend.
         System::Drawing::Size get()
         {
            int legendHeight = chart->Font->Height + 4;
            Graphics^ g = chart->CreateGraphics();
            int legendWidth = (int)g->MeasureString( Name, chart->Font ).Width + 4;
            return System::Drawing::Size( legendWidth, legendHeight );
         }

      }

   };


private:

   // class CurveLegend
   CurveLegend^ legend1;
   CurveLegend^ legend2;

public:
   ChartControl()
   {
      
      // The ChartControl draws the chart in the OnPaint .
      SetStyle( ControlStyles::ResizeRedraw, true );
      SetStyle( ControlStyles::DoubleBuffer, true );
      SetStyle( ControlStyles::AllPaintingInWmPaint, true );
      this->BackColor = System::Drawing::Color::White;
      this->Name = "ChartControl";
      this->Click += gcnew System::EventHandler( this, &ChartControl::ChartControl_Click );
      this->QueryAccessibilityHelp += gcnew System::Windows::Forms::QueryAccessibilityHelpEventHandler( this, &ChartControl::ChartControl_QueryAccessibilityHelp );
      
      // The CurveLengend is not Control-based, it just
      // represents the parts of the legend.
      legend1 = gcnew CurveLegend( this,"A" );
      legend1->Location = Point(20,30);
      legend2 = gcnew CurveLegend( this,"B" );
      legend2->Location = Point(20,50);
   }



protected:
   // Overridden to return the custom AccessibleObject
   // for the entire chart.
   virtual AccessibleObject^ CreateAccessibilityInstance() override
   {
      return gcnew ChartControlAccessibleObject( this );
   }

   virtual void OnPaint( PaintEventArgs^ e ) override
   {
      
      // The ChartControl draws the chart in the OnPaint .
      System::Windows::Forms::UserControl::OnPaint( e );
      Rectangle bounds = this->ClientRectangle;
      int border = 5;
      
      // Draws the legends first.
      StringFormat^ format = gcnew StringFormat;
      format->Alignment = StringAlignment::Center;
      format->LineAlignment = StringAlignment::Center;
      if ( legend1 != nullptr )
      {
         if ( legend1->Selected )
         {
            e->Graphics->FillRectangle( gcnew SolidBrush( Color::Blue ), legend1->Bounds );
         }
         else
         {
            e->Graphics->DrawRectangle( Pens::Blue, legend1->Bounds );
         }

         e->Graphics->DrawString( legend1->Name, this->Font, Brushes::Black, legend1->Bounds, format );
      }

      if ( legend2 != nullptr )
      {
         if ( legend2->Selected )
         {
            e->Graphics->FillRectangle( gcnew SolidBrush( Color::Red ), legend2->Bounds );
         }
         else
         {
            e->Graphics->DrawRectangle( Pens::Red, legend2->Bounds );
         }

         e->Graphics->DrawString( legend2->Name, this->Font, Brushes::Black, legend2->Bounds, format );
      }

      
      // Charts out the actual curves that represent data in the Chart.
      bounds.Inflate(  -border,  -border );
      array<Point>^ temp1 = {Point(bounds.Left,bounds.Bottom),Point(bounds.Left + bounds.Width / 3,bounds.Top + bounds.Height / 5),Point(bounds.Right - bounds.Width / 3,(bounds.Top + bounds.Bottom) / 2),Point(bounds.Right,bounds.Top)};
      array<Point>^curve1 = temp1;
      array<Point>^ temp2 = {Point(bounds.Left,bounds.Bottom - bounds.Height / 3),Point(bounds.Left + bounds.Width / 3,bounds.Top + bounds.Height / 5),Point(bounds.Right - bounds.Width / 3,(bounds.Top + bounds.Bottom) / 2),Point(bounds.Right,bounds.Top + bounds.Height / 2)};
      array<Point>^curve2 = temp2;
      
      // Draws the actual curve only if it is selected.
      if ( legend1->Selected )
            e->Graphics->DrawCurve( Pens::Blue, curve1 );

      if ( legend2->Selected )
            e->Graphics->DrawCurve( Pens::Red, curve2 );

      e->Graphics->DrawRectangle( Pens::Blue, bounds );
   }

   // Handles the QueryAccessibilityHelp event.
   void ChartControl_QueryAccessibilityHelp( Object^ /*sender*/, System::Windows::Forms::QueryAccessibilityHelpEventArgs^ e )
   {
      e->HelpString = "Displays chart data";
   }

   // Handles the Click event for the chart.
   // Toggles the selection of whatever legend was clicked on
   void ChartControl_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      Point pt = this->PointToClient( Control::MousePosition );
      if ( legend1->Bounds.Contains( pt ) )
      {
         legend1->Selected =  !legend1->Selected;
      }
      else
      if ( legend2->Bounds.Contains( pt ) )
      {
         legend2->Selected =  !legend2->Selected;
      }
   }


public:

   property array<CurveLegend^>^ Legends 
   {

      // Gets an array of CurveLengends used in the Chart.
      array<CurveLegend^>^ get()
      {
         array<CurveLegend^>^temp3 = {legend1,legend2};
         return temp3;
      }

   }

   // 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
};


// class ChartControl
public ref class Form1: public System::Windows::Forms::Form
{
private:

   // Test out the Chart Control.
   ChartControl^ chart1;

public:
   Form1()
   {
      
      // Create a chart control and add it to the form.
      this->chart1 = gcnew ChartControl;
      this->ClientSize = System::Drawing::Size( 920, 566 );
      this->chart1->Location = System::Drawing::Point( 47, 16 );
      this->chart1->Size = System::Drawing::Size( 600, 400 );
      this->Controls->Add( this->chart1 );
   }

};


// class Form1

[STAThread]
int main()
{
   Application::Run( gcnew Form1 );
}
using System;
using System.Drawing;
using System.Windows.Forms;

namespace ChartControl
{
    public class Form1 : System.Windows.Forms.Form
    {
        // Test out the Chart Control.
        private ChartControl chart1;

        [STAThread]
        static void Main() 
        {
            Application.Run(new Form1());
        }

        public Form1() {
            // Create a chart control and add it to the form.
            this.chart1 = new ChartControl();
            this.ClientSize = new System.Drawing.Size(920, 566);

            this.chart1.Location = new System.Drawing.Point(47, 16);
            this.chart1.Size = new System.Drawing.Size(600, 400);

            this.Controls.Add(this.chart1);
        }
    }

    // Declare a chart control that demonstrates accessibility in Windows Forms.
    public class ChartControl : System.Windows.Forms.UserControl
    {
        private CurveLegend legend1;
        private CurveLegend legend2; 

        public ChartControl()
        {
            // The ChartControl draws the chart in the OnPaint override.
            SetStyle(ControlStyles.ResizeRedraw, true);
            SetStyle(ControlStyles.DoubleBuffer, true);
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);

            this.BackColor = System.Drawing.Color.White;
            this.Name = "ChartControl";

            this.Click += new System.EventHandler(this.ChartControl_Click);
            this.QueryAccessibilityHelp += 
                new System.Windows.Forms.QueryAccessibilityHelpEventHandler(
                                        this.ChartControl_QueryAccessibilityHelp);

            // The CurveLengend is not Control-based, it just
            // represents the parts of the legend.
            legend1 = new CurveLegend(this, "A");
            legend1.Location = new Point(20, 30);
            legend2 = new CurveLegend(this, "B");        
            legend2.Location = new Point(20, 50);
        }

        // Overridden to return the custom AccessibleObject 
        // for the entire chart.
        protected override AccessibleObject CreateAccessibilityInstance() 
        {            
            return new ChartControlAccessibleObject(this);
        }

        protected override void OnPaint(PaintEventArgs e) 
        {
            // The ChartControl draws the chart in the OnPaint override.
            base.OnPaint(e);

            Rectangle bounds = this.ClientRectangle;
            int border = 5;

            // Draws the legends first.
            StringFormat format = new StringFormat();
            format.Alignment = StringAlignment.Center;
            format.LineAlignment = StringAlignment.Center;
            
            if (legend1 != null) {
                if (legend1.Selected) {
                    e.Graphics.FillRectangle(new SolidBrush(Color.Blue), legend1.Bounds);
                } else {
                    e.Graphics.DrawRectangle(Pens.Blue, legend1.Bounds);
                }

                e.Graphics.DrawString(legend1.Name, this.Font, Brushes.Black, legend1.Bounds, format);                
            }
            if (legend2 != null) {
                if (legend2.Selected) {
                    e.Graphics.FillRectangle(new SolidBrush(Color.Red), legend2.Bounds);
                } else {
                    e.Graphics.DrawRectangle(Pens.Red, legend2.Bounds);
                }
                e.Graphics.DrawString(legend2.Name, this.Font, Brushes.Black, legend2.Bounds, format);
            }            

            // Charts out the actual curves that represent data in the Chart.
            bounds.Inflate(-border, -border);
            Point[] curve1 = new Point[] {new Point(bounds.Left, bounds.Bottom),
                            new Point(bounds.Left + bounds.Width / 3, bounds.Top + bounds.Height / 5),
                            new Point(bounds.Right - bounds.Width / 3, (bounds.Top + bounds.Bottom) / 2),
                            new Point(bounds.Right, bounds.Top)};

            Point[] curve2 = new Point[] {new Point(bounds.Left, bounds.Bottom - bounds.Height / 3),
                            new Point(bounds.Left + bounds.Width / 3, bounds.Top + bounds.Height / 5),
                            new Point(bounds.Right - bounds.Width / 3, (bounds.Top + bounds.Bottom) / 2),
                            new Point(bounds.Right, bounds.Top + bounds.Height / 2)};

            // Draws the actual curve only if it is selected.
            if (legend1.Selected) e.Graphics.DrawCurve(Pens.Blue, curve1);
            if (legend2.Selected) e.Graphics.DrawCurve(Pens.Red, curve2);

            e.Graphics.DrawRectangle(Pens.Blue, bounds);            
        }

        // Handles the QueryAccessibilityHelp event.
        private void ChartControl_QueryAccessibilityHelp(object sender, 
                                    System.Windows.Forms.QueryAccessibilityHelpEventArgs e)
        {            
            e.HelpString = "Displays chart data";
        }          

        // Handles the Click event for the chart. 
        // Toggles the selection of whatever legend was clicked on
        private void ChartControl_Click(object sender, System.EventArgs e)
        {
            Point pt = this.PointToClient(Control.MousePosition);
            if (legend1.Bounds.Contains(pt)) {
                legend1.Selected = !legend1.Selected;
            } else if (legend2.Bounds.Contains(pt)) {
                legend2.Selected = !legend2.Selected;
            }
        }

        // Gets an array of CurveLengends used in the Chart.
        public CurveLegend[] Legends
        {   
            get {                
                return new CurveLegend[] { legend1, legend2 };
            }            
        }                

        // 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 that represents a legend for a curve in the chart.
        public class CurveLegend 
        {
            private string name;
            private ChartControl chart;
            private CurveLegendAccessibleObject accObj;
            private bool selected = true;
            private Point location;

            public CurveLegend(ChartControl chart, string name) 
            {
                this.chart = chart;
                this.name = name;
            }

            // Gets the accessibility object for the curve legend.
            public AccessibleObject AccessibilityObject
            {
                get
                {
                    accObj ??= new CurveLegendAccessibleObject(this);
                    return accObj;
                }
            }
            
            // Gets the bounds for the curve legend.
            public Rectangle Bounds
            {   
                get
                {
                    return new Rectangle(Location, Size);
                }
            }

            // Gets or sets the location for the curve legend.
            public Point Location
            {   
                get {
                    return location;
                }
                set {
                    location = value;
                    chart.Invalidate();

                    // Notifies the chart of the location change. This is used for
                    // the accessibility information. AccessibleEvents.LocationChange
                    // tells the chart the reason for the notification.

                    chart.AccessibilityNotifyClients(AccessibleEvents.LocationChange, 
                        ((CurveLegendAccessibleObject)AccessibilityObject).ID);
                }
            }            
        
            // Gets or sets the Name for the curve legend.
            public string Name
            {   
                get {
                    return name;
                }
                set {
                    if (name != value) 
                    {
                        name = value;
                        chart.Invalidate();

                        // Notifies the chart of the name change. This is used for
                        // the accessibility information. AccessibleEvents.NameChange
                        // tells the chart the reason for the notification.

                        chart.AccessibilityNotifyClients(AccessibleEvents.NameChange, 
                            ((CurveLegendAccessibleObject)AccessibilityObject).ID);
                    }
                }
            }

            // Gets or sets the Selected state for the curve legend.
            public bool Selected
            {   
                get {
                    return selected;
                }
                set {
                    if (selected != value) 
                    {
                        selected = value;
                        chart.Invalidate();

                        // Notifies the chart of the selection value change. This is used for
                        // the accessibility information. The AccessibleEvents value depends upon
                        // if the selection is true (AccessibleEvents.SelectionAdd) or 
                        // false (AccessibleEvents.SelectionRemove).
                        chart.AccessibilityNotifyClients(
                            selected ? AccessibleEvents.SelectionAdd : AccessibleEvents.SelectionRemove, 
                            ((CurveLegendAccessibleObject)AccessibilityObject).ID);
                    }
                }
            }

            // Gets the Size for the curve legend.
            public Size Size
            {   
                get {                    
                    int legendHeight = chart.Font.Height + 4;
                    Graphics g = chart.CreateGraphics();
                    int legendWidth = (int)g.MeasureString(Name, chart.Font).Width + 4;            

                    return new Size(legendWidth, legendHeight);
                }
            }
    
            // 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);
                }
            }
        }
    }
}
Option Explicit

Imports System.Drawing
Imports System.Windows.Forms

Namespace ChartControlNameSpace
    
    Public Class Form1 
        Inherits System.Windows.Forms.Form

        ' Test out the Chart Control.
        Private chart1 As ChartControl

        <System.STAThread()> _
        Public Shared Sub Main()
            System.Windows.Forms.Application.Run(New Form1())
        End Sub

        Public Sub New() 
            ' Create a chart control and add it to the form.
            Me.chart1 = New ChartControl()
            Me.ClientSize = New System.Drawing.Size(920, 566)

            Me.chart1.Location = New System.Drawing.Point(47, 16)
            Me.chart1.Size = New System.Drawing.Size(600, 400)

            Me.Controls.Add(Me.chart1)
        End Sub
    End Class

    ' Declares a chart control that demonstrates Accessibility in Windows Forms.
    Public Class ChartControl
        Inherits System.Windows.Forms.UserControl

        Private legend1 As CurveLegend
        Private legend2 As CurveLegend
        
        Public Sub New()
            ' The ChartControl draws the chart in the OnPaint override.
            SetStyle(ControlStyles.ResizeRedraw, True)
            SetStyle(ControlStyles.DoubleBuffer, True)
            SetStyle(ControlStyles.AllPaintingInWmPaint, True)
            
            Me.BackColor = System.Drawing.Color.White
            Me.Name = "ChartControl"

            ' The CurveLengend is not Control-based, it just
            ' represent the parts of the legend.
            legend1 = New CurveLegend(Me, "A")
            legend1.Location = New Point(20, 30)
            legend2 = New CurveLegend(Me, "B")
            legend2.Location = New Point(20, 50)
        End Sub
              
        ' Overridden to return the custom AccessibleObject 
        ' for the entire chart.
        Protected Overrides Function CreateAccessibilityInstance() As AccessibleObject
            Return New ChartControlAccessibleObject(Me)
        End Function 

        Protected Overrides Sub OnPaint(e As PaintEventArgs)
            ' The ChartControl draws the chart in the OnPaint override.
            MyBase.OnPaint(e)
            
            Dim bounds As Rectangle = Me.ClientRectangle
            Dim border As Integer = 5
            
            ' Draw the legends first.
            Dim format As New StringFormat()
            format.Alignment = StringAlignment.Center
            format.LineAlignment = StringAlignment.Center
            
            If (legend1 IsNot Nothing) Then
                If legend1.Selected Then
                    e.Graphics.FillRectangle(New SolidBrush(Color.Blue), legend1.Bounds)
                Else
                    e.Graphics.DrawRectangle(Pens.Blue, legend1.Bounds)
                End If
                e.Graphics.DrawString(legend1.Name, Me.Font, Brushes.Black, RectangleF.op_Implicit(legend1.Bounds), format)
            End If
            If (legend2 IsNot Nothing) Then
                If legend2.Selected Then
                    e.Graphics.FillRectangle(New SolidBrush(Color.Red), legend2.Bounds)
                Else
                    e.Graphics.DrawRectangle(Pens.Red, legend2.Bounds)
                End If
                e.Graphics.DrawString(legend2.Name, Me.Font, Brushes.Black, RectangleF.op_Implicit(legend2.Bounds), format)
            End If
            
            ' Chart out the actual curves that represent data in the Chart.
            bounds.Inflate(-border, -border)
            Dim curve1() As Point = {New Point(bounds.Left, bounds.Bottom), _
                                     New Point(bounds.Left + bounds.Width / 3, bounds.Top + bounds.Height / 5), _
                                     New Point(bounds.Right - bounds.Width / 3,(bounds.Top + bounds.Bottom) / 2), _
                                     New Point(bounds.Right, bounds.Top)}

            Dim curve2() As Point = {New Point(bounds.Left, bounds.Bottom - bounds.Height / 3), _
                                     New Point(bounds.Left + bounds.Width / 3, bounds.Top + bounds.Height / 5), _
                                     New Point(bounds.Right - bounds.Width / 3,(bounds.Top + bounds.Bottom) / 2), _
                                     New Point(bounds.Right, bounds.Top + bounds.Height / 2)}
            
            ' Draw the actual curve only if it is selected.
            If legend1.Selected Then
                e.Graphics.DrawCurve(Pens.Blue, curve1)
            End If
            If legend2.Selected Then
                e.Graphics.DrawCurve(Pens.Red, curve2)
            End If 
            e.Graphics.DrawRectangle(Pens.Blue, bounds)
        End Sub
        
        ' Handle the QueryAccessibilityHelp event.
        Private Sub ChartControl_QueryAccessibilityHelp(sender As Object, _
                           e As System.Windows.Forms.QueryAccessibilityHelpEventArgs) Handles MyBase.QueryAccessibilityHelp
            e.HelpString = "Displays chart data"
        End Sub 

        ' Handle the Click event for the chart. 
        ' Toggle the selection of whatever legend was clicked.     
        Private Sub ChartControl_Click(sender As Object, e As System.EventArgs) Handles MyBase.Click

            Dim pt As Point = Me.PointToClient(Control.MousePosition)
            If legend1.Bounds.Contains(pt) Then
                legend1.Selected = Not legend1.Selected
            Else
                If legend2.Bounds.Contains(pt) Then
                    legend2.Selected = Not legend2.Selected
                End If
            End If
        End Sub

        ' Get an array of the CurveLengends used in the Chart.
        Public ReadOnly Property Legends() As CurveLegend()
            Get
                Return New CurveLegend() {legend1, legend2}
            End Get
        End Property
        
        Protected Sub ExposeAccessibilityNotifyClients(ByVal accEvent As AccessibleEvents, ByVal childID As Integer)
            AccessibilityNotifyClients(accEvent, childID) 
        End Sub

        ' 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

        ' Inner Class that represents a legend for a curve in the chart.
        Public Class CurveLegend
            Private m_name As String
            Private chart As ChartControl
            Private accObj As CurveLegendAccessibleObject
            Private m_selected As Boolean = True
            Private m_location As Point
            
            Public Sub New(chart As ChartControl, name As String)
                Me.chart = chart
                Me.m_name = name
            End Sub

            ' Gets the accessibility object for the curve legend.            
            Public ReadOnly Property AccessibilityObject() As AccessibleObject
                Get
                    If accObj Is Nothing Then
                        accObj = New CurveLegendAccessibleObject(Me)
                    End If
                    Return accObj
                End Get
            End Property
            
            ' Gets the bounds for the curve legend.            
            Public ReadOnly Property Bounds() As Rectangle
                Get
                    Return New Rectangle(Location, Size)
                End Get
            End Property

            ' Gets or sets the location for the curve legend.            
            Public Property Location() As Point
                Get
                    Return m_location
                End Get
                Set
                    m_location = value
                    chart.Invalidate()

                    ' Notifies the chart of the location change. This is used for
                    ' the accessibility information. AccessibleEvents.LocationChange
                    ' tells the chart the reason for the notification.
                    chart.ExposeAccessibilityNotifyClients(AccessibleEvents.LocationChange, _
                            CType(AccessibilityObject, CurveLegendAccessibleObject).ID)
                End Set
            End Property
            
            ' Gets or sets the Name for the curve legend.            
            Public Property Name() As String
                Get
                    Return m_name
                End Get
                Set
                    If m_name <> value Then
                        m_name = value
                        chart.Invalidate()

                        ' Notifies the chart of the name change. This is used for
                        ' the accessibility information. AccessibleEvents.NameChange
                        ' tells the chart the reason for the notification. 
                        chart.ExposeAccessibilityNotifyClients(AccessibleEvents.NameChange, _
                                CType(AccessibilityObject, CurveLegendAccessibleObject).ID)
                    End If
                End Set
            End Property
            
            ' Gets or sets the Selected state for the curve legend.            
            Public Property Selected() As Boolean
                Get
                    Return m_selected
                End Get
                Set
                    If m_selected <> value Then
                        m_selected = value
                        chart.Invalidate()

                        ' Notifies the chart of the selection value change. This is used for
                        ' the accessibility information. The AccessibleEvents value varies
                        ' on whether the selection is true (AccessibleEvents.SelectionAdd) or 
                        ' false (AccessibleEvents.SelectionRemove). 
                        If m_selected Then
                            chart.ExposeAccessibilityNotifyClients(AccessibleEvents.SelectionAdd, _
                                    CType(AccessibilityObject, CurveLegendAccessibleObject).ID) 
                        Else
                            chart.ExposeAccessibilityNotifyClients(AccessibleEvents.SelectionRemove, _
                                    CType(AccessibilityObject, CurveLegendAccessibleObject).ID) 
                        End If
                    End If
                End Set
            End Property
            
            ' Gets the Size for the curve legend.            
            Public ReadOnly Property Size() As Size
                Get
                    Dim legendHeight As Integer = chart.Font.Height + 4
                    Dim g As Graphics = chart.CreateGraphics()
                    Dim legendWidth As Integer = CInt(g.MeasureString(Name, chart.Font).Width) + 4
                    
                    Return New Size(legendWidth, legendHeight)
                End Get
            End Property
            
            
            ' 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

        End Class

    End Class

End Namespace 'ChartControlNameSpace

備註

協助工具應用程式可以調整應用程式的功能,以改善身心障礙使用者的可用性。

對於視覺受損的使用者,您可以調整軟體和作業系統功能,以符合其需求。 例如,您可以放大文字和影像,並以對比呈現它們。 此外,您也可以使用適當的色彩來容納色盲。 對於嚴重視覺受損的使用者,電腦可以使用螢幕檢閱輔助工具,將螢幕文字轉譯為語音,或轉譯為動態、可重新整理、Braille 顯示器。

對於難以聽覺的使用者,您可以設計使用視覺提示的程式,例如閃爍工具列;或者,您可以將口語訊息顯示為文字。 例如,當開啟時, SoundSentry 此功能是主控台中的協助工具選項,會在系統發出警示音效時提供視覺警告。

對於動作障礙的使用者,您可以設計可精簡或消除鍵盤和滑鼠使用的控制項,藉此改善電腦協助工具。 主控台提供協助。 例如,其中一個替代方法是使用數值按鍵板,而不是滑鼠來進行流覽。 另一個選項稱為 StickyKeys ,可讓使用者一次無法按住兩個或多個按鍵 (,例如 CTRL+P) ,藉由一次輸入一個按鍵來取得相同的結果。

對於認知和語言障礙的使用者,您可以設計軟體程式,以更符合其需求。 例如,使用複雜或提示排序、不復雜顯示、較少字組,以及以基礎學校標準為目標的閱讀層級,可讓這些使用者受益。

對於有疾病的使用者,您可以設計軟體程式來消除疾病疾病模式。

如需協助工具的詳細資訊,包括協助工具應用程式的相關資訊,請參閱 Windows 協助工具功能

注意

若要使用 AccessibleObject ,您必須將參考新增至 Accessibility 隨 .NET Framework 一起安裝的元件。 Windows Forms僅支援 Active Accessibility 2.0。

給繼承者的注意事項

當您繼承自這個類別時,可以覆寫所有成員。

建構函式

AccessibleObject()

初始化 AccessibleObject 類別的新執行個體。

屬性

Bounds

取得可存取物件的位置和大小。

DefaultAction

取得描述物件之預設動作的字串。 並非所有的物件都有預設動作。

Description

取得描述指定物件之視覺外觀的字串。 並非所有的物件都有描述。

Help

取得物件的用途或物件使用方式的描述。

KeyboardShortcut

取得可存取物件的快速鍵或便捷鍵 (Access Key)。

Name

取得或設定物件名稱。

Parent

取得可存取之物件的父系。

Role

取得這個可存取之物件的角色。

State

取得這個可存取物件的狀態。

Value

取得或設定可存取物件的數值。

方法

CreateObjRef(Type)

建立包含所有相關資訊的物件,這些資訊是產生用來與遠端物件通訊的所需 Proxy。

(繼承來源 MarshalByRefObject)
DoDefaultAction()

執行與這個可存取物件相關的預設動作。

Equals(Object)

判斷指定的物件是否等於目前的物件。

(繼承來源 Object)
GetChild(Int32)

擷取與指定索引相對應的可存取子系。

GetChildCount()

擷取屬於可存取物件的子系數目。

GetFocused()

擷取具有鍵盤焦點的物件。

GetHashCode()

做為預設雜湊函式。

(繼承來源 Object)
GetHelpTopic(String)

取得說明主題識別項的識別項,以及與這個可存取物件相關之通往說明檔的路徑。

GetLifetimeService()
已淘汰.

擷取控制這個執行個體存留期 (Lifetime) 原則的目前存留期服務物件。

(繼承來源 MarshalByRefObject)
GetSelected()

擷取目前選取的子系。

GetType()

取得目前執行個體的 Type

(繼承來源 Object)
HitTest(Int32, Int32)

擷取位於指定螢幕座標的子物件。

InitializeLifetimeService()
已淘汰.

取得存留期服務物件,以控制這個執行個體的存留期原則。

(繼承來源 MarshalByRefObject)
MemberwiseClone()

建立目前 Object 的淺層複製。

(繼承來源 Object)
MemberwiseClone(Boolean)

建立目前 MarshalByRefObject 物件的淺層複本。

(繼承來源 MarshalByRefObject)
Navigate(AccessibleNavigation)

可巡覽到另一個可存取物件。

RaiseAutomationNotification(AutomationNotificationKind, AutomationNotificationProcessing, String)

引發使用者介面自動化通知事件。

RaiseLiveRegionChanged()

引發 LiveRegionChanged 使用者介面自動化事件。

Select(AccessibleSelection)

修改選取或者移動可存取物件的鍵盤焦點。

ToString()

傳回代表目前物件的字串。

(繼承來源 Object)
UseStdAccessibleObjects(IntPtr)

根據物件的控制代碼,將物件與 AccessibleObject 的執行個體產生關聯。

UseStdAccessibleObjects(IntPtr, Int32)

根據物件的控制代碼和物件 ID,將物件與 AccessibleObject 的執行個體產生關聯。

明確介面實作

IAccessible.accChildCount

取得屬於這個物件的子介面數目。 如需這個成員的說明,請參閱 accChildCount

IAccessible.accDoDefaultAction(Object)

執行指定物件的預設動作。 並非所有的物件都有預設動作。 如需這個成員的說明,請參閱 accDoDefaultAction(Object)

IAccessible.accFocus

取得具有鍵盤焦點的物件。 如需這個成員的說明,請參閱 accFocus

IAccessible.accHitTest(Int32, Int32)

取得位於指定螢幕座標的子物件。 如需這個成員的說明,請參閱 accHitTest(Int32, Int32)

IAccessible.accLocation(Int32, Int32, Int32, Int32, Object)

取得物件的目前螢幕位置。 如需這個成員的說明,請參閱 accLocation(Int32, Int32, Int32, Int32, Object)

IAccessible.accNavigate(Int32, Object)

巡覽至相對於目前物件的可存取物件。 如需這個成員的說明,請參閱 accNavigate(Int32, Object)

IAccessible.accParent

取得這個物件的可存取父物件。 如需這個成員的說明,請參閱 accParent

IAccessible.accSelect(Int32, Object)

修改選取或者移動可存取物件的鍵盤焦點。 如需這個成員的說明,請參閱 accSelect(Int32, Object)

IAccessible.accSelection

取得可存取物件的選定子物件。 如需這個成員的說明,請參閱 accSelection

IReflect.GetField(String, BindingFlags)

取得對應到指定欄位和繫結旗標的 FieldInfo 物件。 如需這個成員的說明,請參閱 GetField(String, BindingFlags)

IReflect.GetFields(BindingFlags)

取得對應到目前類別的所有欄位之 FieldInfo 物件陣列。 如需這個成員的說明,請參閱 GetFields(BindingFlags)

IReflect.GetMember(String, BindingFlags)

取得 MemberInfo 物件陣列,其會對應到所有公用成員或所有符合指定名稱的成員。 如需這個成員的說明,請參閱 GetMember(String, BindingFlags)

IReflect.GetMembers(BindingFlags)

取得 MemberInfo 物件陣列,其會對應到所有公用成員或目前類別的所有成員。 如需這個成員的說明,請參閱 GetMembers(BindingFlags)

IReflect.GetMethod(String, BindingFlags)

取得 MethodInfo 物件,其會對應到指定搜尋條件約束下的指定方法。 如需這個成員的說明,請參閱 GetMethod(String, BindingFlags)

IReflect.GetMethod(String, BindingFlags, Binder, Type[], ParameterModifier[])

使用 Type 陣列從多載方法中選擇,取得對應到指定方法的 MethodInfo 物件。 如需這個成員的說明,請參閱 GetMethod(String, BindingFlags, Binder, Type[], ParameterModifier[])

IReflect.GetMethods(BindingFlags)

取得包含所有公用方法或目前類別的所有方法的 MethodInfo 物件陣列。 如需這個成員的說明,請參閱 GetMethods(BindingFlags)

IReflect.GetProperties(BindingFlags)

取得 PropertyInfo 物件陣列,其會對應到所有公用屬性或目前類別的所有屬性。 如需這個成員的說明,請參閱 GetProperties(BindingFlags)

IReflect.GetProperty(String, BindingFlags)

取得 PropertyInfo 物件,其會對應到指定搜尋條件約束下的指定屬性。 如需這個成員的說明,請參閱 GetProperty(String, BindingFlags)

IReflect.GetProperty(String, BindingFlags, Binder, Type, Type[], ParameterModifier[])

取得 PropertyInfo 物件,其會對應到具有指定搜尋條件約束的指定屬性。 如需這個成員的說明,請參閱 GetProperty(String, BindingFlags, Binder, Type, Type[], ParameterModifier[])

IReflect.InvokeMember(String, BindingFlags, Binder, Object, Object[], ParameterModifier[], CultureInfo, String[])

叫用指定成員。 如需這個成員的說明,請參閱 InvokeMember(String, BindingFlags, Binder, Object, Object[], ParameterModifier[], CultureInfo, String[])

IReflect.UnderlyingSystemType

取得表示 IReflect 物件的基礎型別。 如需這個成員的說明,請參閱 UnderlyingSystemType

適用於