AccessibleStates 列舉

參考

定義

命名空間:: System.Windows.Forms

組件:: System.Windows.Forms.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

指定數值，代表可存取物件的可能狀態。

此列舉支援其成員值的位元組合。

public enum class AccessibleStates

[System.Flags]
public enum AccessibleStates

[<System.Flags>]
type AccessibleStates =

Public Enum AccessibleStates

繼承: Object

ValueType

Enum
AccessibleStates

屬性: FlagsAttribute

欄位

AlertHigh	268435456	應立刻傳達給使用者的重要資訊。例如，剩餘電量指示器 (Indicator) 到達關鍵性的低電位時就會轉換成這個狀態，這種情況下，盲目存取公用程式會立刻向使用者宣告這項資訊，而且螢幕縮放程式會捲動螢幕，讓電量指示器進入檢視當中。這個狀態也適用於必須先完成，使用者才能夠繼續的任何提示或作業。
AlertLow	67108864	對使用者可能並不重要的低優先權資訊。
AlertMedium	134217728	不必立刻傳達給使用者的重要資訊。例如，剩餘電量指示器開始達到低電位時，可產生中級的警告。然後盲目存取公用程式就會產生聲響，讓使用者知道有重要資訊，而不真正中斷使用者的工作。使用者就可以在所選擇的時間隨時查詢警告資訊。
Animated	16384	快速或經常要變更外觀的物件。偶爾但並非一定會使用動畫效果的圖形，應該定義成 Graphic`ORAnimated`。此一狀態不應該用於指示物件變位置。
Busy	2048	無法在目前的條件中接受輸入的控制項。
Checked	16	具有選定核取方塊的物件。
Collapsed	1024	是大綱或樹狀結構中之項目的物件隱藏子系。
Default	256	預設按鈕或功能表項目。
Expanded	512	是大綱或樹狀結構中之項目的物件顯示子系。
ExtSelectable	33554432	變更的選取項目會使選取項目錨點 (也就是具有鍵盤焦點的物件) 之間的所有物件和這個物件取得錨點物件的選取項目狀態。如果不選取錨點物件，物件會從選取項目移除。如果選取錨點物件，選取項目會擴充，來包含這個物件和之間所有的物件。您可以將這個和 AddSelection 或 RemoveSelection 組合，來設定選取項目的狀態。這個狀態除非與 TakeFocus 組合，否則不會變更焦點或選取項目的錨點。
Floating	4096	不固定在父物件之界限的物件和不隨著父系自動移動的物件。
Focusable	1048576	使用中視窗上可接收鍵盤焦點的物件。
Focused	4	具有鍵盤焦點的物件。
HasPopup	1073741824	物件被叫用時會顯示快顯功能表或視窗。
HotTracked	128	滑鼠熱點追蹤的物件，表示它的外觀反白顯示，來指示出滑鼠指標位在它的上方。
Indeterminate	32	狀態不定的三態核取方塊或工具列按鈕。核取方塊不是已選取也不是未核取，是在第三種或混合狀態中。
Invisible	32768	沒有可見的使用者介面的物件。
Linked	4194304	先前尚未選取的已連結物件。
Marqueed	8192	具有捲動或移動文字或圖形的物件。
Mixed	32	狀態不定的三態核取方塊或工具列按鈕。核取方塊不是已選取也不是未核取，是在第三種或混合狀態中。
Moveable	262144	可移動的物件。
MultiSelectable	16777216	接受多重選取項目的物件。
None	0	沒有狀態。
Offscreen	65536	沒有螢幕上的表示。聲音或警告物件，或永遠不可見的隱藏視窗可具有這個狀態。
Pressed	8	按下的物件。
Protected	536870912	密碼保護的編輯控制項。
ReadOnly	64	唯讀的物件。
Selectable	2097152	可接受選取項目的物件。
Selected	2	選取的物件。
SelfVoicing	524288	物件或子系可使用文字到語音 (TTS) 的方式來自我描述。當具有這個狀態的物件擁有焦點時，因為物件會自動宣告有關本身的資訊，所以語音為主的輔助工具不應宣告資訊。
Sizeable	131072	可調大小的物件。
Traversed	8388608	先前已選取的已連結物件。
Unavailable	1	不可用的物件。
Valid	1073741823	有效的物件。此屬性在 .NET Framework 2.0 中已被取代。

範例

下列程式碼範例示範如何使用 AccessibleObject 和 Control.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。因為圖表圖例不是根據 Control 的實際控制項，而是由圖表控制項繪製，所以它不包含任何內建的可存取訊號。因此，類別 ChartControlAccessibleObject 會 GetChild 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。

此程式碼摘錄示範如何搭配 State 屬性使用 AccessibleStates 列舉。 AccessibleObject如需完整的程式碼範例，請參閱類別概觀。

// 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

備註

可存取的物件可以與其中一或多個狀態相關聯。

適用於

AccessibleStates 列舉

定義

欄位

範例

備註

適用於

另請參閱

其他資源