Silverlight printing_问答_开发者_运维开发者技术经验分享

What are my options for printing in Silverlight 3? Assume I have this awesome Silverlight application/control that creates a graphical display of some data. Now the user wants to print it.

I have considered a few options but I have yet to test any of these. Before I do that I would like to get some feedback on how it can be done.

Use the browser printing capabilites. In my experience this is does not provide a useful print, but perhaps with some interaction between the Silverlight host and the browser it can be done?
Use WriteableBitmap. The image can either be written locally, but this requires interaction from the user, or sent to the server where a suitable file (e.g. PDF file) can be generated and then sent back to the browser. Unfortunately you now get the overhead of sending the image twice across the network and increased complexity on the server side.
Send XAML back to the server that is then rendered in a WPF application running on the server. The result is the sent back to the client. I'm not sure if this is possible at all however, but if it is the network overhead is less than in option 2. Unfortunately, the complexity on the server side is even higher.
Wait for Silverlight 4?

One thing I have considered is that my awesome control probably will have a ScrollViewer at the highest level, but the user will want to print the entire content of the control, not just whatever is visible inside the bounds of the 开发者_StackOverflowScrollViewer. How can I handle this added complexity?

In all seriousness, I think your best option is to wait until Silverlight 4 if your client can wait that long. I've seen a good bit of buzz about SL 4 supporting printing on twitter, though it's not official. I'd wait until PDC in a few weeks and see if any Silverlight bits trickle out to support printing.

Take a look at SmartPrint for Silverlight 3: http://www.smartwebcontrols.com/SmartPrintDetails.aspx

TBH I wouldn't use any of those options:-

Printing from the browser. Fine if you are printing say a chart or something else that scales well on a single sheet of paper. Rubbish for anything else especially where you have scrolled content.
WriteableBitmap. I can't see a client-side only solution being acceptable to the user "Please save this and then print it" message. It could be made to work bouncing off the server but would be bad for bandwidth use (bandwidth is import right? because in a well-connect intranet you wouldn't using Silverlight?).
Sending XAML to server for rendering. Really awkward it would be WPF XAML not SL XAML, where and how would you do the binding, why send XAML at all, since the server needs to be pretty much clued in on this so why can't it hold the XAML needed as well. Or were you thinking of sending just pure XAML with all the data needed? Still its a lot of plumbing needed in the SL that isn't actually related to SL.
Use Silverlight 4, its possible that in the not to distant future this would be the correct no-brainer choice (personally I wouldn't hold my breath) but right now SL4 doesn't exist.

A 5th option

Place report generating code on the server and have the Silverlight app inform the server of the data set required (not necessarily posting the data merely the criteria needed to access the correct set). In my experience direct prints of GUIs aren't particularly satisfactory when the user really needs a good printed form of the data.

Its true that at times the user just wants to quickly get some offline access to a grid of data as it looks there and then. In that situation users often find an export to spreadsheet compatible file preferable to printing, which would be possible from SL.

Something akin to number two is pretty much your best bet and is what I've seen done for printing in most Silverlight apps so far.

You can have the app send content for printing back to the web server (i.e. a new handler or query string parameters to a printing page) and pop up another page for the user to print web content from, or you could allow the user to download a file and have them print that.

Sliverlight 3 does not support printing.

If you can wait for silverlight 4, they have given it "high priority"

If not use Writeablebitmap: http://www.andybeaulieu.com/Home/tabid/67/EntryID/161/Default.aspx