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Obter atributos de texto usando a automação da interface do usuário

Nota

Esta documentação destina-se a desenvolvedores do .NET Framework que desejam usar as classes de automação da interface do usuário gerenciadas definidas no System.Windows.Automation namespace. Para obter as informações mais recentes sobre a automação da interface do usuário, consulte API de automação do Windows: automação da interface do usuário.

Este tópico mostra como usar a Automação da Interface do Usuário da Microsoft para obter atributos de texto de um intervalo de texto. Um intervalo de texto pode corresponder à localização atual do cursor (ou seleção degenerada) dentro de um documento, uma seleção contígua de texto, uma coleção de seleções de texto separadas ou todo o conteúdo textual de um documento.

Exemplo

O exemplo de código a seguir demonstra como obter o FontNameAttribute de um intervalo de texto.

/// -------------------------------------------------------------------
/// <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

O TextPattern padrão de controle, em conjunto com a TextPatternRange classe, oferece suporte a atributos, propriedades e métodos básicos de texto. Para funcionalidade específica de controle que não é suportada por TextPattern ou TextPatternRange a AutomationElementclasse , fornece métodos para um cliente de automação da interface do usuário acessar o modelo de objeto nativo correspondente.

Consulte também

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