Changing FixedDocumentPresenter(nullException)

[Eric]

I am getting a null reference exception whenever assigning to the RadPdfViewer FixedDocumentPresenter property. The last line of code below is where an exception is thrown. I have also tried to set the FixedDocumentPresenter property by using pdfViewer.GetRegisteredPresenter(), but I get the same exception. I need the presenter to be set so I can get coordinates of the PDF but the value is null.

            pdfViewer = new RadPdfViewer();
            string pdfFilePath = "C:\\temp\\GeneratedDocument.pdf";
            MemoryStream stream = new MemoryStream();
            using (Stream input = File.OpenRead(pdfFilePath))
            {
                input.CopyTo(stream);
            }
            FormatProviderSettings settings = new FormatProviderSettings(ReadingMode.OnDemand);
            PdfFormatProvider provider = new PdfFormatProvider(stream, settings);
            RadFixedDocument doc = provider.Import();
            pdfViewer.Document = doc;
            pdfViewer.MouseDoubleClick += PdfViewer_MouseDoubleClick;

            var myPresenter = new FixedDocumentSinglePageViewPresenter();
            pdfViewer.FixedDocumentPresenter = myPresenter;

 

EXCEPTION:Error Message: Object reference not set to an instance of an object.

   at Telerik.Windows.Controls.FixedDocumentViewerBase.InitializeFixedDocumentPresenter(IFixedDocumentPresenter releasedPresenter, IFixedDocumentPresenter presenter)
   at Telerik.Windows.Controls.FixedDocumentViewerBase.set_FixedDocumentPresenter(IFixedDocumentPresenter value)

 

[Polya]

Hello Eric,

The reason for this exception is that the RadPdfViewer is not added in the UI tree, which is required in order for the control to initialize its context, which then initializes its FixedDocumentPresenter.
That said, you need to include the pdfViewer in the UI tree (for example add it in the parent Grid) and call ApplyTemplate() so that everything is initialized before the FixedDocumentPresenter is changed: 

pdfViewer = new RadPdfViewer();
string pdfFilePath = "C:\\temp\\GeneratedDocument.pdf";
MemoryStream stream = new MemoryStream();
using (Stream input = File.OpenRead(pdfFilePath))
{
    input.CopyTo(stream);
}
FormatProviderSettings settings = new FormatProviderSettings(ReadingMode.OnDemand);
PdfFormatProvider provider = new PdfFormatProvider(stream, settings);
RadFixedDocument doc = provider.Import();
pdfViewer.Document = doc;
pdfViewer.MouseDoubleClick += PdfViewer_MouseDoubleClick;

this.grid.Children.Add(pdfViewer);
pdfViewer.ApplyTemplate();

var myPresenter = new FixedDocumentSinglePageViewPresenter();
pdfViewer.FixedDocumentPresenter = myPresenter;

If you do not wish to display the pdfViewer you could set its Visibility to Collapsed.

In order for us to get a better understanding of what you wish to achieve, I would like to ask you to elaborate more on your scenario: why are you using a new instance of RadPdfViewer, which is not added to the UI of your application; what do you wish to change using a new FixedDocumentPresenter? 
Looking forward to your reply.

Regards,
Polya
Progress Telerik