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在 UI 自动化提供程序中支持控件模式

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备注

本文档适用于想要使用 System.Windows.Automation 命名空间中定义的托管 UI 自动化类的 .NET Framework 开发人员。 有关 UI 自动化的最新信息，请参阅 Windows 自动化 API：UI 自动化。

本主题演示如何在 UI 自动化提供程序上实现一个或多个控件模式，以便客户端应用程序可以操作控件并从中获取数据。

支持控件模式

  1. 为元素应支持的控件模式实现相应的接口，例如为 为 IInvokeProvider 实现 InvokePattern。

  2. 返回包含 IRawElementProviderSimple.GetPatternProvider实现中每个控件接口的实现的对象

示例 1

下面的示例演示了对单项选择自定义列表框实现 ISelectionProvider 。 它返回三个属性并获取当前所选的项。

#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

示例 2

下面的示例演示了返回实现 GetPatternProvider 的类的 ISelectionProvider的实现。 大多数列表框控件还支持其他模式，但在本示例中对所有其他模式标识符返回了空引用（Microsoft Visual Basic .NET 中的 Nothing）。

/// <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

请参阅