AccessibleStates 枚举

参考

定义

命名空间:: System.Windows.Forms

程序集:: System.Windows.Forms.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

指定表示辅助性对象的可能状态的值。

此枚举支持其成员值的按位组合。

public enum class AccessibleStates

[System.Flags]
public enum AccessibleStates

[<System.Flags>]
type AccessibleStates =

Public Enum AccessibleStates

继承: Object

ValueType

Enum
AccessibleStates

属性: FlagsAttribute

字段

AlertHigh	268435456	应该立即传达给用户的重要信息。例如，降低到临界低电平的电池电量指示器将转换为此状态，这种情况下，盲访问实用工具会立即将该信息通知给用户，并且屏幕放大程序会滚动屏幕，以便能够看到电池指示器。此状态也适用于任何提示或用户在能够继续操作之前必须要先完成的操作。
AlertLow	67108864	对于用户或许不重要的低优先级信息。
AlertMedium	134217728	不需要立即传达给用户的重要信息。例如，当电池电量指示器即将达到低电平时，它会生成中级警报。然后，盲访问实用工具会发出声音，使用户知道有重要信息，而实际并不中断用户的工作。用户可以在任何选定时间查询警报信息。
Animated	16384	迅速或经常更改外观的对象。偶尔会动（并非一直在动）的图形应该定义为 Graphic`ORAnimated`。此状态不应用来指示对象的位置正在更改。
Busy	2048	不能在其当前条件下接受输入的控件。
Checked	16	具有选中的复选框的对象。
Collapsed	1024	对象的隐藏子级，这些子级是大纲或树结构中的项。
Default	256	默认按钮或菜单项。
Expanded	512	对象的显示子级，这些子级是大纲或树结构中的项。
ExtSelectable	33554432	改动的选择，其中，选择定位点之间的所有对象（带有键盘焦点的对象）以及此对象都采用定位点对象的选择状态。如果没有选择定位点对象，对象就会从所选内容中移除。如果选择了定位点对象，所选内容就会扩展至包括此对象以及定位点之间的所有对象。您可以通过将它与 AddSelection 或 RemoveSelection 结合使用来设置所选内容状态。此状态不会更改焦点或选择定位点，除非将它与 TakeFocus 结合使用。
Floating	4096	没有固定到其父对象的边界的对象和不会随父对象一起自动移动的对象。
Focusable	1048576	可接收键盘焦点的活动窗口上的对象。
Focused	4	具有键盘焦点的对象。
HasPopup	1073741824	该对象在调用会显示弹出菜单或窗口。
HotTracked	128	由鼠标热跟踪的对象，意味着其外观突出显示以表示鼠标指针停留在其上。
Indeterminate	32	状态不确定的三态复选框或工具栏按钮。复选框既不处于选中状态也不处于未选中状态，而是处于第三种状态或混合状态。
Invisible	32768	没有可视用户界面的对象。
Linked	4194304	以前没有选择的链接对象。
Marqueed	8192	具有滚动或移动文本或图形的对象。
Mixed	32	状态不确定的三态复选框或工具栏按钮。复选框既不处于选中状态也不处于未选中状态，而是处于第三种状态或混合状态。
Moveable	262144	可移动对象。
MultiSelectable	16777216	接受多个选定项的对象。
None	0	无状态。
Offscreen	65536	无屏幕表示形式。声音或警报对象，或者从不呈现可视状态的隐藏窗口，都会具有此状态。
Pressed	8	被按下的对象。
Protected	536870912	有密码保护的编辑控件。
ReadOnly	64	只读对象。
Selectable	2097152	可以接受所选内容的对象。
Selected	2	选定的对象。
SelfVoicing	524288	对象或子级可以使用“文字到语音”（TTS）来描述自己。当具有此状态的对象有焦点时，基于语音的辅助功能不会通告信息，因为对象会自动通告有关它自身的信息。
Sizeable	131072	可调整大小的对象。
Traversed	8388608	以前已选择的链接对象。
Unavailable	1	不可用的对象。
Valid	1073741823	有效的对象。 .NET Framework 2.0 中弃用此属性。

示例

下面的代码示例演示了如何使用 AccessibleObject 和 Control.ControlAccessibleObject 类公开可访问性图表控件来创建辅助功能感知图表控件。该控件绘制两条曲线以及图例。派 ChartControlAccessibleObject 生自 ControlAccessibleObject的 CreateAccessibilityInstance 类用于提供图表控件的自定义可访问信息。由于图表图例不是基于 Control的实际控件，而是由图表控件绘制，因此它不包含任何内置的可访问信息。因此，类 ChartControlAccessibleObject 会重写 GetChild 该方法以返回 CurveLegendAccessibleObject 表示图例的每个部分的可访问信息的方法。当可访问感知应用程序使用此控件时，该控件可以提供必要的可访问信息。

此代码摘录演示了将 AccessibleStates 枚举与属性结合使用 State 。 AccessibleObject有关完整的代码示例，请参阅类概述。

// 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

注解

可访问的对象可以与其中一个或多个状态相关联。

适用于

通过

AccessibleStates 枚举

定义

字段

示例

注解

适用于

另请参阅

其他资源