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本文档的目标读者是欲使用 System.Windows.Automation 命名空间中定义的托管 UI Automation类的 .NET Framework 开发人员。有关 UI Automation的最新信息，请参见 Windows Automation API: UI Automation（Windows 自动化 API：UI 自动化）。 |
本主题演示如何使用 Microsoft UI Automation从跨越多个特性值的文本范围中获取文本特性详细信息。文本范围可以与文档、连续选择的文本、非连续选择的文本集合或文档的整个文本内容中的插入符号的当前位置相对应（或使选择范围退化）。
示例
下面的代码示例演示如何从文本范围（GetAttributeValue 从此文本范围中返回 MixedAttributeValue 对象）中获取 FontNameAttribute。
'--------------------------------------------------------------------
' <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();
}
与 TextPatternRange 类结合使用时，TextPattern 控件模式支持基本的文本特性、属性和方法。 对于 TextPattern 或 TextPatternRange 不支持的特定于控件的功能，AutomationElement 类将为 UI 自动化客户端提供访问相应本机对象模型的方法。