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Tekstkenmerken verkrijgen met behulp van UI Automation

Notitie

Deze documentatie is bedoeld voor .NET Framework-ontwikkelaars die de beheerde UI Automation-klassen willen gebruiken die zijn gedefinieerd in de System.Windows.Automation naamruimte. Zie Windows Automation-API: UI Automation voor de meest recente informatie over UI Automation.

In dit onderwerp wordt beschreven hoe u Microsoft UI Automation gebruikt om tekstkenmerken op te halen uit een tekstbereik. Een tekstbereik kan overeenkomen met de huidige locatie van de caret (of selectie degenereren) in een document, een aaneengesloten selectie van tekst, een verzameling niet-aaneengesloten tekstselecties of de volledige tekstinhoud van een document.

Opmerking

In het volgende codevoorbeeld ziet u hoe u het FontNameAttribute kunt verkrijgen uit een tekstbereik.

/// -------------------------------------------------------------------
/// <summary>
/// Starts the target application and returns the AutomationElement
/// obtained from the targets window handle.
/// </summary>
/// <param name="exe">
/// The target application.
/// </param>
/// <param name="filename">
/// The text file to be opened in the target application
/// </param>
/// <returns>
/// An AutomationElement representing the target application.
/// </returns>
/// -------------------------------------------------------------------
private AutomationElement StartTarget(string exe, string filename)
{
    // Start text editor and load with a text file.
    Process p = Process.Start(exe, filename);

    // targetApp --> the root AutomationElement.
    AutomationElement targetApp =
        AutomationElement.FromHandle(p.MainWindowHandle);

    return targetApp;
}

''' -------------------------------------------------------------------
''' <summary>
''' Starts the target application and returns the AutomationElement 
''' obtained from the targets window handle.
''' </summary>
''' <param name="exe">
''' The target application.
''' </param>
''' <param name="filename">
''' The text file to be opened in the target application
''' </param>
''' <returns>
''' An AutomationElement representing the target application.
''' </returns>
''' -------------------------------------------------------------------
Private Function StartTarget( _
ByVal exe As String, ByVal filename As String) As AutomationElement
    ' Start text editor and load with a text file.
    Dim p As Process = Process.Start(exe, filename)

    ' targetApp --> the root AutomationElement.
    Dim targetApp As AutomationElement
    targetApp = AutomationElement.FromHandle(p.MainWindowHandle)

    Return targetApp
End Function

/// -------------------------------------------------------------------
/// <summary>
/// Obtain the text control of interest from the target application.
/// </summary>
/// <param name="targetApp">
/// The target application.
/// </param>
/// <returns>
/// An AutomationElement that represents a text provider..
/// </returns>
/// -------------------------------------------------------------------
private AutomationElement GetTextElement(AutomationElement targetApp)
{
    // The control type we're looking for; in this case 'Document'
    PropertyCondition cond1 =
        new PropertyCondition(
        AutomationElement.ControlTypeProperty,
        ControlType.Document);

    // The control pattern of interest; in this case 'TextPattern'.
    PropertyCondition cond2 =
        new PropertyCondition(
        AutomationElement.IsTextPatternAvailableProperty,
        true);

    AndCondition textCondition = new AndCondition(cond1, cond2);

    AutomationElement targetTextElement =
        targetApp.FindFirst(TreeScope.Descendants, textCondition);

    // If targetText is null then a suitable text control was not found.
    return targetTextElement;
}

''' -------------------------------------------------------------------
''' <summary>
''' Obtain the text control of interest from the target application.
''' </summary>
''' <param name="targetApp">
''' The target application.
''' </param>
''' <returns>
''' An AutomationElement. representing a text control.
''' </returns>
''' -------------------------------------------------------------------
Private Function GetTextElement(ByVal targetApp As AutomationElement) As AutomationElement
    ' The control type we're looking for; in this case 'Document'
    Dim cond1 As PropertyCondition = _
        New PropertyCondition( _
        AutomationElement.ControlTypeProperty, _
        ControlType.Document)

    ' The control pattern of interest; in this case 'TextPattern'.
    Dim cond2 As PropertyCondition = _
        New PropertyCondition( _
        AutomationElement.IsTextPatternAvailableProperty, _
        True)

    Dim textCondition As AndCondition = New AndCondition(cond1, cond2)

    Dim targetTextElement As AutomationElement = _
        targetApp.FindFirst(TreeScope.Descendants, textCondition)

    ' If targetText is null then a suitable text control was not found.
    Return targetTextElement
End Function

/// -------------------------------------------------------------------
/// <summary>
/// Outputs the FontNameAttribute value for a range of text.
/// </summary>
/// <param name="targetTextElement">
/// The AutomationElement that represents a text control.
/// </param>
/// -------------------------------------------------------------------
private void GetFontNameAttribute(AutomationElement targetTextElement)
{
    TextPattern textPattern =
        targetTextElement.GetCurrentPattern(TextPattern.Pattern) as TextPattern;

    if (textPattern == null)
    {
        // Target control doesn't support TextPattern.
        return;
    }

    // If the target control doesn't support selection then return.
    // Otherwise, get the text attribute for the selected text.
    // If there are currently no selections then the text attribute
    // will be obtained from the insertion point.
    TextPatternRange[] textRanges;
    if (textPattern.SupportedTextSelection == SupportedTextSelection.None)
    {
        return;
    }
    else
    {
        textRanges = textPattern.GetSelection();
    }

    foreach (TextPatternRange textRange in textRanges)
    {
        Object textAttribute =
            textRange.GetAttributeValue(
            TextPattern.FontNameAttribute);

        if (textAttribute == TextPattern.MixedAttributeValue)
        {
            // Returns MixedAttributeValue if the value of the
            // specified attribute varies over the text range.
            Console.WriteLine("Mixed fonts.");
        }
        else if (textAttribute == AutomationElement.NotSupported)
        {
            // Returns NotSupported if the specified attribute is
            // not supported by the provider or the control.
            Console.WriteLine(
                "FontNameAttribute not supported by provider.");
        }
        else
        {
            Console.WriteLine(textAttribute.ToString());
        }
    }
}

''' -------------------------------------------------------------------
''' <summary>
''' Outputs the FontNameAttribute value for a range of text.
''' </summary>
''' <param name="targetTextElement">
''' The AutomationElement. that represents the text provider.
''' </param>
''' -------------------------------------------------------------------
Private Sub GetFontNameAttribute( _
ByVal targetTextElement As AutomationElement)
    Dim targetTextPattern As TextPattern = _
        DirectCast(targetTextElement.GetCurrentPattern( _
        TextPattern.Pattern), TextPattern)

    If (targetTextPattern Is Nothing) Then
        ' Target control doesn't support TextPattern.
        Return
    End If

    ' If the target control doesn't support selection then return.
    ' Otherwise, get the text attribute for the selected text.
    ' If there are currently no selections then the text attribute 
    ' will be obtained from the insertion point.
    Dim textRanges() As TextPatternRange
    If (targetTextPattern.SupportedTextSelection = SupportedTextSelection.None) Then
        Return
    Else
        textRanges = targetTextPattern.GetSelection()
    End If

    Dim textRange As TextPatternRange
    For Each textRange In textRanges
        Dim textAttribute As Object = _
            textRange.GetAttributeValue( _
            TextPattern.FontNameAttribute)

        If (textAttribute = TextPattern.MixedAttributeValue) Then
            ' Returns MixedAttributeValue if the value of the 
            ' specified attribute varies over the text range. 
            Console.WriteLine("Mixed fonts.")
        ElseIf (textAttribute = AutomationElement.NotSupported) Then
            ' Returns NotSupported if the specified attribute is 
            ' not supported by the provider or the control. 
            Console.WriteLine( _
            "FontNameAttribute not supported by provider.")
        Else
            Console.WriteLine(textAttribute.ToString())
        End If
    Next
End Sub

Het TextPattern besturingspatroon ondersteunt in combinatie met de TextPatternRange klasse basistekstkenmerken, eigenschappen en methoden. Voor besturingsspecifieke functionaliteit die niet wordt ondersteund door TextPattern of TextPatternRange de AutomationElementklasse biedt methoden voor een UI Automation-client voor toegang tot het bijbehorende systeemeigen objectmodel.

Zie ook

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