使用 UI 自动化向文本框添加内容
备注
本文档适用于想要使用 System.Windows.Automation 命名空间中定义的托管 UI 自动化类的 .NET Framework 开发人员。 有关 UI 自动化的最新信息，请参阅 Windows 自动化 API：UI 自动化。
本主题包含示例代码，该代码演示如何使用 Microsoft UI 自动化将文本插入单行文本框中。 UI 自动化不适用时，为多行和 RTF 控件提供备用方法。 出于比较目的，示例还演示了如何使用 Win32 方法来实现相同的结果。
示例
下面的示例逐步介绍目标应用程序中的一系列文本控件。 对每个文本控件进行了测试，以查看是否可以使用 TryGetCurrentPattern 方法从中获取 ValuePattern 对象。 如果文本控件确实支持 ValuePattern，则使用 SetValue 方法将用户定义的字符串插入到文本控件中。 否则，使用 SendKeys.SendWait 方法。
///--------------------------------------------------------------------
/// <summary>
/// Sets the values of the text controls using managed methods.
/// </summary>
/// <param name="s">The string to be inserted.</param>
///--------------------------------------------------------------------
private void SetValueWithUIAutomation(string s)
{
foreach (AutomationElement control in textControls)
{
InsertTextUsingUIAutomation(control, s);
}
}
///--------------------------------------------------------------------
/// <summary>
/// Inserts a string into each text control of interest.
/// </summary>
/// <param name="element">A text control.</param>
/// <param name="value">The string to be inserted.</param>
///--------------------------------------------------------------------
private void InsertTextUsingUIAutomation(AutomationElement element,
string value)
{
try
{
// Validate arguments / initial setup
if (value == null)
throw new ArgumentNullException(
"String parameter must not be null.");
if (element == null)
throw new ArgumentNullException(
"AutomationElement parameter must not be null");
// A series of basic checks prior to attempting an insertion.
//
// Check #1: Is control enabled?
// An alternative to testing for static or read-only controls
// is to filter using
// PropertyCondition(AutomationElement.IsEnabledProperty, true)
// and exclude all read-only text controls from the collection.
if (!element.Current.IsEnabled)
{
throw new InvalidOperationException(
"The control with an AutomationID of "
+ element.Current.AutomationId.ToString()
+ " is not enabled.\n\n");
}
// Check #2: Are there styles that prohibit us
// from sending text to this control?
if (!element.Current.IsKeyboardFocusable)
{
throw new InvalidOperationException(
"The control with an AutomationID of "
+ element.Current.AutomationId.ToString()
+ "is read-only.\n\n");
}
// Once you have an instance of an AutomationElement,
// check if it supports the ValuePattern pattern.
object valuePattern = null;
// Control does not support the ValuePattern pattern
// so use keyboard input to insert content.
//
// NOTE: Elements that support TextPattern
// do not support ValuePattern and TextPattern
// does not support setting the text of
// multi-line edit or document controls.
// For this reason, text input must be simulated
// using one of the following methods.
//
if (!element.TryGetCurrentPattern(
ValuePattern.Pattern, out valuePattern))
{
feedbackText.Append("The control with an AutomationID of ")
.Append(element.Current.AutomationId.ToString())
.Append(" does not support ValuePattern.")
.AppendLine(" Using keyboard input.\n");
// Set focus for input functionality and begin.
element.SetFocus();
// Pause before sending keyboard input.
Thread.Sleep(100);
// Delete existing content in the control and insert new content.
SendKeys.SendWait("^{HOME}"); // Move to start of control
SendKeys.SendWait("^+{END}"); // Select everything
SendKeys.SendWait("{DEL}"); // Delete selection
SendKeys.SendWait(value);
}
// Control supports the ValuePattern pattern so we can
// use the SetValue method to insert content.
else
{
feedbackText.Append("The control with an AutomationID of ")
.Append(element.Current.AutomationId.ToString())
.Append((" supports ValuePattern."))
.AppendLine(" Using ValuePattern.SetValue().\n");
// Set focus for input functionality and begin.
element.SetFocus();
((ValuePattern)valuePattern).SetValue(value);
}
}
catch (ArgumentNullException exc)
{
feedbackText.Append(exc.Message);
}
catch (InvalidOperationException exc)
{
feedbackText.Append(exc.Message);
}
finally
{
Feedback(feedbackText.ToString());
}
}
'' --------------------------------------------------------------------
'' <summary>
'' Sets the values of the text controls using managed methods.
'' </summary>
'' <param name="s">The string to be inserted.</param>
'' --------------------------------------------------------------------
Private Sub SetValueWithUIAutomation(ByVal s As String)
Dim control As AutomationElement
For Each control In textControls
InsertTextWithUIAutomation(control, s)
Next control
End Sub
'' --------------------------------------------------------------------
'' <summary>
'' Inserts a string into each text control of interest.
'' </summary>
'' <param name="element">A text control.</param>
'' <param name="value">The string to be inserted.</param>
'' --------------------------------------------------------------------
Private Sub InsertTextWithUIAutomation( _
ByVal element As AutomationElement, ByVal value As String)
Try
' Validate arguments / initial setup
If value Is Nothing Then
Throw New ArgumentNullException( _
"String parameter must not be null.")
End If
If element Is Nothing Then
Throw New ArgumentNullException( _
"AutomationElement parameter must not be null")
End If
' A series of basic checks prior to attempting an insertion.
'
' Check #1: Is control enabled?
' An alternative to testing for static or read-only controls
' is to filter using
' PropertyCondition(AutomationElement.IsEnabledProperty, true)
' and exclude all read-only text controls from the collection.
If Not element.Current.IsEnabled Then
Throw New InvalidOperationException( _
"The control with an AutomationID of " + _
element.Current.AutomationId.ToString() + _
" is not enabled." + vbLf + vbLf)
End If
' Check #2: Are there styles that prohibit us
' from sending text to this control?
If Not element.Current.IsKeyboardFocusable Then
Throw New InvalidOperationException( _
"The control with an AutomationID of " + _
element.Current.AutomationId.ToString() + _
"is read-only." + vbLf + vbLf)
End If
' Once you have an instance of an AutomationElement,
' check if it supports the ValuePattern pattern.
Dim targetValuePattern As Object = Nothing
' Control does not support the ValuePattern pattern
' so use keyboard input to insert content.
'
' NOTE: Elements that support TextPattern
' do not support ValuePattern and TextPattern
' does not support setting the text of
' multi-line edit or document controls.
' For this reason, text input must be simulated
' using one of the following methods.
'
If Not element.TryGetCurrentPattern(ValuePattern.Pattern, targetValuePattern) Then
feedbackText.Append("The control with an AutomationID of ") _
.Append(element.Current.AutomationId.ToString()) _
.Append(" does not support ValuePattern."). _
AppendLine(" Using keyboard input.").AppendLine()
' Set focus for input functionality and begin.
element.SetFocus()
' Pause before sending keyboard input.
Thread.Sleep(100)
' Delete existing content in the control and insert new content.
SendKeys.SendWait("^{HOME}") ' Move to start of control
SendKeys.SendWait("^+{END}") ' Select everything
SendKeys.SendWait("{DEL}") ' Delete selection
SendKeys.SendWait(value)
Else
' Control supports the ValuePattern pattern so we can
' use the SetValue method to insert content.
feedbackText.Append("The control with an AutomationID of ") _
.Append(element.Current.AutomationId.ToString()) _
.Append(" supports ValuePattern.") _
.AppendLine(" Using ValuePattern.SetValue().").AppendLine()
' Set focus for input functionality and begin.
element.SetFocus()
Dim valueControlPattern As ValuePattern = _
DirectCast(targetValuePattern, ValuePattern)
valueControlPattern.SetValue(value)
End If
Catch exc As ArgumentNullException
feedbackText.Append(exc.Message)
Catch exc As InvalidOperationException
feedbackText.Append(exc.Message)
Finally
Feedback(feedbackText.ToString())
End Try
End Sub