Obtain Mixed Text Attribute Details Using UI Automation
This topic shows how to use Microsoft UI Automation to obtain text attribute details from a text range that spans multiple attribute values. A text range can correspond to the current location of the caret (or degenerate selection) within a document, a contiguous selection of text, a collection of disjoint text selections, or the entire textual content of a document.
Example
The following code example demonstrates how to obtain the FontNameAttribute from a text range where GetAttributeValue returns a MixedAttributeValue object.
'--------------------------------------------------------------------
' <summary>
' Display the target selection with attribute details in client.
' </summary>
' <param name="selectedText">The current target selection.</param>
'--------------------------------------------------------------------
Private Sub DisplaySelectedTextWithAttributes(ByVal selectedText As String)
targetSelection.Text = selectedText
' We're only interested in the FontNameAttribute for the purposes
' of this sample.
targetSelectionAttributes.Text = _
ParseTextRangeByAttribute( _
selectedText, TextPattern.FontNameAttribute)
End Sub
'--------------------------------------------------------------------
' <summary>
' Parse the target selection based on the text attribute of interest.
' </summary>
' <param name="selectedText">The current target selection.</param>
' <param name="automationTextAttribute">
' The text attribute of interest.
' </param>
' <returns>
' A string representing the requested attribute details.
' </returns>
'--------------------------------------------------------------------
Function ParseTextRangeByAttribute( _
ByVal selectedText As String, _
ByVal automationTextAttribute As AutomationTextAttribute) As String
Dim attributeDetails As StringBuilder = New StringBuilder()
' Initialize the current attribute value.
Dim attributeValue As String = ""
' Make a copy of the text range.
Dim searchRangeClone As TextPatternRange = searchRange.Clone()
' Collapse the range to the starting endpoint.
searchRangeClone.Move(TextUnit.Character, -1)
' Iterate through the range character by character.
Dim x As Integer
For x = 1 To selectedText.Length
searchRangeClone.Move(TextUnit.Character, 1)
' Get the attribute value of the current character.
Dim newAttributeValue As String = _
searchRangeClone.GetAttributeValue(automationTextAttribute).ToString()
' If the new attribute value is not equal to the old then report
' the new value along with its location within the range.
If (newAttributeValue <> attributeValue) Then
attributeDetails.Append(automationTextAttribute.ProgrammaticName) _
.Append(":") _
.Append(vbLf) _
.Append("<") _
.Append(newAttributeValue) _
.Append("> at text range position ") _
.AppendLine(x.ToString())
attributeValue = newAttributeValue
End If
Next
Return attributeDetails.ToString()
End Function
///--------------------------------------------------------------------
/// <summary>
/// Display the target selection with attribute details in client.
/// </summary>
/// <param name="selectedText">The current target selection.</param>
///--------------------------------------------------------------------
private void DisplaySelectedTextWithAttributes(string selectedText)
{
targetSelection.Text = selectedText;
// We're only interested in the FontNameAttribute for the purposes
// of this sample.
targetSelectionAttributes.Text =
ParseTextRangeByAttribute(
selectedText, TextPattern.FontNameAttribute);
}
///--------------------------------------------------------------------
/// <summary>
/// Parse the target selection based on the text attribute of interest.
/// </summary>
/// <param name="selectedText">The current target selection.</param>
/// <param name="automationTextAttribute">
/// The text attribute of interest.
/// </param>
/// <returns>
/// A string representing the requested attribute details.
/// </returns>
///--------------------------------------------------------------------
private string ParseTextRangeByAttribute(
string selectedText,
AutomationTextAttribute automationTextAttribute)
{
StringBuilder attributeDetails = new StringBuilder();
// Initialize the current attribute value.
string attributeValue = "";
// Make a copy of the text range.
TextPatternRange searchRangeClone = searchRange.Clone();
// Collapse the range to the starting endpoint.
searchRangeClone.Move(TextUnit.Character, -1);
// Iterate through the range character by character.
for (int x = 1; x <= selectedText.Length; x+)
{
searchRangeClone.Move(TextUnit.Character, 1);
// Get the attribute value of the current character.
string newAttributeValue =
searchRangeClone.GetAttributeValue(automationTextAttribute).ToString();
// If the new attribute value is not equal to the old then report
// the new value along with its location within the range.
if (newAttributeValue != attributeValue)
{
attributeDetails.Append(automationTextAttribute.ProgrammaticName)
.Append(":\n<")
.Append(newAttributeValue)
.Append("> at text range position ")
.AppendLine(x.ToString());
attributeValue = newAttributeValue;
}
}
return attributeDetails.ToString();
}
The TextPattern control pattern, in tandem with the TextPatternRange class, supports basic text attributes, properties, and methods. For control-specific functionality that is not supported by TextPattern or TextPatternRange, the AutomationElement class provides methods for a UI Automation client to access the corresponding native object model.
See Also
Tasks
Add Content to a Text Box Using UI Automation
Find and Highlight Text Using UI Automation
Obtain Text Attributes Using UI Automation
Concepts
UI Automation TextPattern Overview