Эта версия VB.Net подходит для моей ситуации. Я удалил семафор коллекции потоков, вместо этого используя RemoveHandler и AddHandler. Кроме того, поскольку FlowDocument может быть привязан только к одному RichTextBox за раз, я поставил проверку, что RichTextBox IsLoaded = True. Давайте начнем с того, как я использовал класс в приложении MVVM, которое использует ResourceDictionary вместо Window.
' Loaded and Unloaded events seems to be the only way to initialize a control created from a Resource Dictionary
' Loading document here because Loaded is the last available event to create a document
Private Sub Rtb_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
' only good place to initialize RichTextBox.Document with DependencyProperty
Dim rtb As RichTextBox = DirectCast(sender, RichTextBox)
Try
rtb.Document = RichTextBoxHelper.GetDocumentXaml(rtb)
Catch ex As Exception
Debug.WriteLine("Rtb_Loaded: Message:" & ex.Message)
End Try
End Sub
' Loaded and Unloaded events seems to be the only way to initialize a control created from a Resource Dictionary
' Free document being held by RichTextBox.Document by assigning New FlowDocument to RichTextBox.Document. Otherwise we'll see an of "Document belongs to another RichTextBox"
Private Sub Rtb_Unloaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs)
Dim rtb As RichTextBox = DirectCast(sender, RichTextBox)
Dim fd As New FlowDocument
RichTextBoxHelper.SetDocumentXaml(rtb, fd)
Try
rtb.Document = fd
Catch ex As Exception
Debug.WriteLine("PoemDocument.PoemDocumentView.PoemRtb_Unloaded: Message:" & ex.Message)
End Try
End Sub
Public Class RichTextBoxHelper
Inherits DependencyObject
Public Shared Function GetDocumentXaml(ByVal depObj As DependencyObject) As FlowDocument
Return depObj.GetValue(DocumentXamlProperty)
End Function
Public Shared Sub SetDocumentXaml(ByVal depObj As DependencyObject, ByVal value As FlowDocument)
depObj.SetValue(DocumentXamlProperty, value)
End Sub
Public Shared ReadOnly DocumentXamlProperty As DependencyProperty = DependencyProperty.RegisterAttached("DocumentXaml", GetType(FlowDocument), GetType(RichTextBoxHelper), New FrameworkPropertyMetadata(Nothing, FrameworkPropertyMetadataOptions.AffectsRender Or FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, Sub(depObj, e)
RegisterIt(depObj, e)
End Sub))
Private Shared Sub RegisterIt(ByVal depObj As System.Windows.DependencyObject, ByVal e As System.Windows.DependencyPropertyChangedEventArgs)
Dim rtb As RichTextBox = DirectCast(depObj, RichTextBox)
If rtb.IsLoaded Then
RemoveHandler rtb.TextChanged, AddressOf TextChanged
Try
rtb.Document = GetDocumentXaml(rtb)
Catch ex As Exception
Debug.WriteLine("RichTextBoxHelper.RegisterIt: ex:" & ex.Message)
rtb.Document = New FlowDocument()
End Try
AddHandler rtb.TextChanged, AddressOf TextChanged
Else
Debug.WriteLine("RichTextBoxHelper: Unloaded control ignored:" & rtb.Name)
End If
End Sub
' When a RichTextBox Document changes, update the DependencyProperty so they're in sync.
Private Shared Sub TextChanged(ByVal sender As Object, ByVal e As TextChangedEventArgs)
Dim rtb As RichTextBox = TryCast(sender, RichTextBox)
If rtb IsNot Nothing Then
SetDocumentXaml(sender, rtb.Document)
End If
End Sub
End Class