Fix empty receiver signature when sending

EnvelopeGenerator.Form/Controllers/EnvelopeEditorController.vb

@@ -33,6 +33,11 @@ Public Class EnvelopeEditorController
     Public Function SendEnvelope() As Boolean
         For Each receiverItem As EnvelopeReceiver In Envelope.Receivers
 
+            If receiverItem.Signature Is Nothing Then
+                Logger.Warn("Signature for Receiver is empty. Aborting.")
+                Return False
+            End If
+
             Dim oEmailData As New EmailData(Envelope, receiverItem) With
             {
                 .SignatureLink = Helpers.GetEnvelopeURL(State.DbConfig.SignatureHost, Envelope.Uuid, receiverItem.Signature)
@@ -266,22 +271,16 @@ Public Class EnvelopeEditorController
     End Function
 
     Public Function CreateEnvelopeReceivers(pCurrentReceivers As List(Of EnvelopeReceiver)) As Boolean
-        Dim oExistingReceivers As List(Of EnvelopeReceiver) = ReceiverModel.ListReceivers(pCurrentReceivers)
+        Dim oExistingReceivers As List(Of EnvelopeReceiver) = ReceiverModel.ListReceivers(pCurrentReceivers).ToList()
         Dim oExistingAddresses = oExistingReceivers.Select(Function(r) r.Email)
 
         ' Neue Empfänger
         Dim oNewReceivers = pCurrentReceivers.
                 Where(Function(r) Not oExistingAddresses.Contains(r.Email)).ToList()
 
-        ' Empfänger, die bereits einmal verwendet wurden
-        For Each oCurrentReceiver In pCurrentReceivers
-            If oCurrentReceiver.Id = 0 Then
-                Dim oExistingReceiver As EnvelopeReceiver = oExistingReceivers.Where(Function(r) r.Email.Equals(oCurrentReceiver.Email, StringComparison.InvariantCultureIgnoreCase)).FirstOrDefault()
-                If oExistingReceiver IsNot Nothing Then
-                    oCurrentReceiver.Id = oExistingReceiver.Id
-                End If
-            End If
-        Next
+        If oNewReceivers.Count = 0 Then
+            Return True
+        End If
 
         Dim oConnection = Database.GetConnection()
         Dim oTransaction = oConnection.BeginTransaction()
@@ -293,6 +292,9 @@ Public Class EnvelopeEditorController
 
             oTransaction.Commit()
 
+            ' Empfänger neu aus der Datenbank laden
+            Envelope.Receivers = ReceiverModel.ListReceivers(pCurrentReceivers).ToList()
+
             Return True
         Catch ex As Exception
             Logger.Error(ex)