XPS suppress navigateuri error for custom URL

Question

We are trying to view an XPS document using a Document Viewer as follows ( VB.NET code )

oDoc = New Xps.Packaging.XpsDocument(path:=sDocument, packageAccess:=IO.FileAccess.Read)
oSequence = oDoc.GetFixedDocumentSequence
oDocViewer.Document = oSequence

The second line causes it to throw an error
System.Windows.Markup.XamlParseException: ''Failed to create a 'NavigateUri' from the text .....

With an inner exception
Invalid URI: The hostname could not be parsed.

The URI in question, however, is a custom one, something like:
mylittlecustomprotocol://tonsandtonsofencryptedgarbagehere

The protocol handler we wrote for this has no problem with it. So we were hoping that there is a way to suppress this error for the mylittlecustomprotocol protocol

Answer 1

For self-generated xps files with custom hyperlinks, you need to add RequestNavigate to the hyperlinks. Then you can navigate the hyperlink to your target file.
The code of the project that generates the xps file:

Imports System.IO  
Imports System.IO.Packaging  
Imports System.Windows.Xps.Packaging  
Imports System.Windows.Xps.Serialization  
  
Partial Public Class MainWindow  
    Inherits Window  
  
    Public Sub New()  
        InitializeComponent()  
    End Sub  
  
    Private Sub Hyperlink_RequestNavigate(ByVal sender As Object, ByVal e As System.Windows.Navigation.RequestNavigateEventArgs)  
        Process.Start(New ProcessStartInfo(e.Uri.AbsoluteUri))  
        e.Handled = True  
    End Sub  
  
    Private Sub Window_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)  
        Dim myParagraph As Paragraph = New Paragraph()  
        Dim run1 As Run = New Run("mylittlecustomprotocol://tonsandtonsofencryptedgarbagehere")  
        Dim h1 As Hyperlink = New Hyperlink(run1)  
        h1.NavigateUri = New Uri("mylittlecustomprotocol://tonsandtonsofencryptedgarbagehere")  
        AddHandler h1.RequestNavigate, AddressOf Hyperlink_RequestNavigate  
  
        myParagraph.Inlines.Add(h1)  
        Dim myFlowDocument As FlowDocument = New FlowDocument()  
        myFlowDocument.Blocks.Add(myParagraph)  
        Me.Content = myFlowDocument  
        Dim ftx As FlowToXps = New FlowToXps()  
        ftx.SaveAsXps("C:\\...\\tt.xps", myFlowDocument)  
    End Sub  
End Class  
  
Public Class FlowToXps  
    Public Sub SaveAsXps(ByVal path As String, ByVal document As FlowDocument)  
        Using package As Package = Package.Open(path, FileMode.Create)  
  
            Using xpsDoc = New XpsDocument(package, CompressionOption.Maximum)  
                Dim xpsSm = New XpsSerializationManager(New XpsPackagingPolicy(xpsDoc), False)  
                Dim dp As DocumentPaginator = (CType(document, IDocumentPaginatorSource)).DocumentPaginator  
                xpsSm.SaveAsXaml(dp)  
            End Using  
        End Using  
    End Sub  
End Class  

The code of the project that reads the xps file:

Imports System.IO  
Imports System.Windows.Xps.Packaging  
Partial Public Class MainWindow  
    Public Sub New()  
        InitializeComponent()  
        Dim ogXps = "C:\\...\\tt.xps"  
        Dim xpsDoc As XpsDocument = New XpsDocument(ogXps, FileAccess.Read)  
        Dim seqDoc As FixedDocumentSequence = xpsDoc.GetFixedDocumentSequence()  
        dv.Document = seqDoc  
    End Sub  
End Class  

The result is shown in the figure: