Support Control Patterns in a UI Automation Provider
This topic shows how to implement one or more control patterns on a UI Automation provider so that client applications can manipulate controls and get data from them.
Support Control Patterns
Implement the appropriate interfaces for the control patterns that the element should support, such as IInvokeProvider for InvokePattern.
Return the object containing your implementation of each control interface in your implementation of IRawElementProviderSimple.GetPatternProvider
Example
The following example shows an implementation of ISelectionProvider for a single-selection custom list box. It returns three properties and gets the currently selected item.
#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
#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
The following example shows an implementation of GetPatternProvider that returns the class implementing ISelectionProvider. Most list box controls would support other patterns as well, but in this example a null reference (Nothing in Microsoft Visual Basic .NET) is returned for all other pattern identifiers.
''' <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
/// <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;
}
}