There is no native C#/XAML PDF viewing component for Windows Store applications, but there are a growing number of options, and various apps have demonstrated success in different areas of PDF rasterization (converting PDF pages to images) and viewing. Here is a breakdown of all the components that I have seen. These are all expensive, so they might not work well for a hobbyist scenario. But if you have a need in your commercial or LOB application, you may find one of these to be useful.
If you learn of others, please post a reply or send me a tweet @paulwhit. I’m actively monitoring this topic.
Also some developers appear to have ported MuPDF for use in Windows Store applications. I believe this is GPL licensed so you would either need to open source your project or buy a license, so use caution there.
If you have the possibility to rasterize the images using a tool external to your Windows Store application, you can create a decent reader experience from a directory of images. Your users will take a bandwidth hit because downloading the rasterized contents can inflate the download size a lot, but at least you can provide the functionality. That is what I did with Army Field Manuals.
In fact, I used GhostScript with a high resolution raster and then used ImageMagick to do an adaptive resize and convert to grayscale. This gave decent quality although some of the scanned pages are still too large due to scanner ghosting in the page background. I think I need to do something to increase the contrast on those particular documents. Anyway, here’s a rundown of the command line arguments I used with those tools in case you want to do something similar.
gswin64c.exe -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 -sDEVICE=png16m -dTextAlphaBits=4 -dGraphicsAlphaBits=4 -r288 -o fm1_0/out_%d.png {pdffilename}
convert {filename} -adaptive-resize 1224x1584 sm_{filename}
mogrify -type grayscale {filename}