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MVVM: load pdf by stream or uri
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This is a migrated thread and some comments may be shown as answers.
cielo valdoz
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cielo valdoz asked on 28 Mar 2012, 07:21 AM
Hi,

I want to load pdf files dynamically to the pdf viewer but the file is not displaying.

<

 

 

telerik:RadPdfViewer Grid.Row="1" HorizontalAlignment="Stretch" Margin="0" DocumentSource="{Binding DocumentStream, Converter={StaticResource DocumentConverter}, ConverterParameter=1}" VerticalAlignment="Stretch" />

 


DocumentStream is binded on the DocumentSource and assigned by this code:
#Region "Property"
  
        Private m_DocumentStream As Stream
        Public Property DocumentStream As Stream
            Get
                Return m_DocumentStream
            End Get
            Set(value As Stream)
                m_DocumentStream = value
                Me.RaisePropertyChanged("DocumentStream")
            End Set
        End Property
#End Region
  
#Region "Sub"
        Private Sub ReadStream(absolutePath As String)
            Dim wc = New WebClient()
            AddHandler wc.OpenReadCompleted, AddressOf OnWebReadCompleted
            wc.OpenReadAsync(New Uri(absolutePath, UriKind.Absolute))
        End Sub
  
        Private Sub OnWebReadCompleted(sender As Object, e As OpenReadCompletedEventArgs)
            ' Read your stream from e.Result
  
            DocumentStream = e.Result
  
        End Sub
#End Region
  
#Region "Navigation"
  
        Public Sub ConfirmNavigationRequest(navigationContext As Microsoft.Practices.Prism.Regions.NavigationContext, continuationCallback As System.Action(Of Boolean)) Implements Microsoft.Practices.Prism.Regions.IConfirmNavigationRequest.ConfirmNavigationRequest
            continuationCallback(True)
        End Sub
  
        Public Function IsNavigationTarget(navigationContext As Microsoft.Practices.Prism.Regions.NavigationContext) As Boolean Implements Microsoft.Practices.Prism.Regions.INavigationAware.IsNavigationTarget
  
        End Function
  
        Public Sub OnNavigatedFrom(navigationContext As Microsoft.Practices.Prism.Regions.NavigationContext) Implements Microsoft.Practices.Prism.Regions.INavigationAware.OnNavigatedFrom
  
        End Sub
  
        Public Sub OnNavigatedTo(navigationContext As Microsoft.Practices.Prism.Regions.NavigationContext) Implements Microsoft.Practices.Prism.Regions.INavigationAware.OnNavigatedTo
            Dim strDocument As String = navigationContext.Parameters("DocumentPath")
  
            ReadStream(strDocument)
        End Sub
  
  
        Public ReadOnly Property KeepAlive As Boolean Implements Microsoft.Practices.Prism.Regions.IRegionMemberLifetime.KeepAlive
            Get
                Return True
            End Get
        End Property
#End Region

Converter for the DocumentStream
Namespace Converter
    Public Class DocumentConverter
        Implements IValueConverter
  
        Public Function Convert(value As Object, targetType As System.Type, parameter As Object, culture As System.Globalization.CultureInfo) As Object Implements System.Windows.Data.IValueConverter.Convert
            Dim file As PdfDocumentSource
            Dim intParam As Integer = CInt(parameter)
            If Not value Is Nothing Then
  
                Select Case intParam
  
                    Case 1 'pdf
                        Using stream As Stream = Application.GetResourceStream(GetResourceUri("documents/test.pdf")).Stream
                            Dim x As Uri
                            x = New Uri("http://localhost:50609/documents/test.pdf")
  
                            file = New PdfDocumentSource(stream)
                            Return file
                        End Using
  
                    Case 2 'word
  
                    Case 3 'excel
  
                End Select
            Else
                Return Nothing
            End If
  
        End Function
  
        Public Function ConvertBack(value As Object, targetType As System.Type, parameter As Object, culture As System.Globalization.CultureInfo) As Object Implements System.Windows.Data.IValueConverter.ConvertBack
  
        End Function
  
        Public Shared Function GetResourceUri(resource As String) As Uri
            Dim assemblyName As New AssemblyName(GetType(DocumentConverter).Assembly.FullName)
            Dim resourcePath As String = "/" + assemblyName.Name + ";component/" + resource
            Dim resourceUri As New Uri(resourcePath, UriKind.Relative)
  
            Return resourceUri
        End Function
    End Class



It's not displaying even if i tried to load from absolute/relative uri
Please help.

Thanks,
Cielo

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Kammen
Telerik team
answered on 28 Mar 2012, 01:09 PM
Hello Cielo,

The problem in your code is that you close your stream before the document is loaded (this is done because of the Using statement). You should note that the DocumentSource loads the document asynchronously. So you can close the stream only when the document is loaded (in the handler of the DocumentSource.Loaded event for example). 

Kind regards,

Kammen
the Telerik team
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cielo valdoz
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answered on 29 Mar 2012, 02:48 AM

Hi,

I added this code and solved my problem. Thanks a lot :)
AddHandler file.Loaded, AddressOf DocEvent_Loaded

 

 

 

Private Sub DocEvent_Loaded(sender As Object, e As System.EventArgs) Handles DocEvent.Loaded

 

 

 


End
Sub

 



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cielo valdoz
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Kammen
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cielo valdoz
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