支援 UI 自動化提供者的控制項模式

注意

這份文件適用於想要使用 UI 自動化 命名空間中定義之 Managed System.Windows.Automation 類別的 .NET Framework 開發人員。 如需 UI 自動化的最新資訊,請參閱 Windows Automation API:UI 自動化

本主題說明如何在使用者介面自動化提供者上實作一個或多個控制項模式,讓用戶端應用程式能夠操作控制項並從中取得資料。

支援控制項模式

  1. 針對項目應該支援的控制項模式,實作適當的介面,例如適用於 IInvokeProviderInvokePattern

  2. IRawElementProviderSimple.GetPatternProvider實作中,傳回包含每個控制項介面實作的物件

範例

下列範例示範單一選取自訂清單方塊的 ISelectionProvider 實作。 它會傳回三個屬性並取得目前選取的項目。

#region ISelectionProvider Members

/// <summary>
/// Specifies whether selection of more than one item at a time is supported.
/// </summary>
public bool CanSelectMultiple
{
    get
    {
        return false;
    }
}

/// <summary>
/// Specifies whether the list has to have an item selected at all times.
/// </summary>
public bool IsSelectionRequired
{
    get
    {
        return true;
    }
}

/// <summary>
/// Returns the automation provider for the selected list item.
/// </summary>
/// <returns>The selected item.</returns>
/// <remarks>
/// MyList is an ArrayList collection of providers for items in the list box.
/// SelectedIndex is the index of the selected item.
/// </remarks>
public IRawElementProviderSimple[] GetSelection()
{
    if (SelectedIndex >= 0)
    {
        IRawElementProviderSimple itemProvider = (IRawElementProviderSimple)MyList[SelectedIndex];
        IRawElementProviderSimple[] providers =  { itemProvider };
        return providers;
    }
    else
    {
        return null;
    }
}
#endregion ISelectionProvider Members
#Region "ISelectionProvider Members"

    ''' <summary>
    ''' Specifies whether selection of more than one item at a time is supported.
    ''' </summary>

    Public ReadOnly Property CanSelectMultiple() As Boolean _
        Implements ISelectionProvider.CanSelectMultiple
        Get
            Return False
        End Get
    End Property
    ''' <summary>
    ''' Specifies whether the list has to have an item selected at all times.
    ''' </summary>

    Public ReadOnly Property IsSelectionRequired() As Boolean _
        Implements ISelectionProvider.IsSelectionRequired
        Get
            Return True
        End Get
    End Property

    ''' <summary>
    ''' Returns the automation provider for the selected list item.
    ''' </summary>
    ''' <returns>The selected item.</returns>
    ''' <remarks>
    ''' MyList is an ArrayList collection of providers for items in the list box.
    ''' SelectedIndex is the index of the selected item.
    ''' </remarks>
    Public Function GetSelection() As IRawElementProviderSimple() _
        Implements ISelectionProvider.GetSelection
        If SelectedIndex >= 0 Then
            Dim itemProvider As IRawElementProviderSimple = DirectCast(MyList(SelectedIndex), IRawElementProviderSimple)
            Dim providers(1) As IRawElementProviderSimple
            providers(0) = itemProvider
            Return providers
        Else
            Return Nothing
        End If

    End Function 'GetSelection 
#End Region
    Private Members As ISelectionProvider

範例

下列範例示範 GetPatternProvider 的實作,它會傳回實作 ISelectionProvider的類別。 大部分的清單方塊控制項也會支援其他模式,但在此範例中, Nothing 會針對所有其他模式識別碼傳回 Microsoft Visual Basic .net) 中 (的 null 參考。

/// <summary>
/// Returns the object that supports the specified pattern.
/// </summary>
/// <param name="patternId">ID of the pattern.</param>
/// <returns>Object that implements IInvokeProvider.</returns>
/// <remarks>
/// In this case, the ISelectionProvider interface is implemented in another provider-defined class,
/// ListPattern. However, it could be implemented in the base provider class, in which case the
/// method would simply return "this".
/// </remarks>
object IRawElementProviderSimple.GetPatternProvider(int patternId)
{
    if (patternId == SelectionPatternIdentifiers.Pattern.Id)
    {
        return new ListPattern(myItems, SelectedIndex);
    }
    else
    {
        return null;
    }
}
''' <summary>
''' Returns the object that supports the specified pattern.
''' </summary>
''' <param name="patternId">ID of the pattern.</param>
''' <returns>Object that implements IInvokeProvider.</returns>
''' <remarks>
''' In this case, the ISelectionProvider interface is implemented in another provider-defined class, 
''' ListPattern. However, it could be implemented in the base provider class, in which case the 
''' method would simply return "this".
''' </remarks>
Function GetPatternProvider(ByVal patternId As Integer) As Object _
    Implements IRawElementProviderSimple.GetPatternProvider

    If patternId = SelectionPatternIdentifiers.Pattern.Id Then
        Return New ListPattern(myItems, SelectedIndex)
    Else
        Return Nothing
    End If

End Function 'IRawElementProviderSimple.GetPatternProvider

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