'''--------------------------------------------------------------------
''' <summary>
''' Inserts a string into a text control that supports ValuePattern.
''' </summary>
''' <param name="targetControl">A text control.</param>
''' <param name="value">The string to be inserted.</param>
'''--------------------------------------------------------------------
Private Sub InsertText(ByVal targetControl As AutomationElement, _
ByVal value As String)
    ' Validate arguments / initial setup
    If value Is Nothing Then
        Throw New ArgumentNullException( _
        "String parameter must not be null.")
    End If

    If targetControl 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 targetControl.Current.IsEnabled Then
        Throw New InvalidOperationException( _
        "The control is not enabled." + vbLf + vbLf)
    End If

    ' Check #2: Are there styles that prohibit us 
    '           from sending text to this control?
    If Not targetControl.Current.IsKeyboardFocusable Then
        Throw New InvalidOperationException( _
        "The control is not focusable." + vbLf + vbLf)
    End If

    ' Once you have an instance of an AutomationElement,  
    ' check if it supports the ValuePattern pattern.
    Dim valuePattern As Object = Nothing

    If Not targetControl.TryGetCurrentPattern( _
    valuePattern.Pattern, valuePattern) Then
        ' 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.
        ' Control supports the ValuePattern pattern so we can 
        ' use the SetValue method to insert content.
    Else
        If CType(valuePattern, ValuePattern).Current.IsReadOnly Then
            Throw New InvalidOperationException("The control is read-only.")
        Else
            CType(valuePattern, ValuePattern).SetValue(value)
        End If
    End If

End Sub