Tuesday, May 11, 2010

Converting XML to PDF

I was looking for an application that would convert an XML file into a PDF document. In fact I was trying to create an invoice as a PDF file were the invoice had originated from Great Plains (an application from the Microsoft Dynamics suite that claims to be an accounts package).

A colleague recommended Aspose.Words for .NET to me as he was using it for another project. It uses a Word document as a template and sets it up as a mailmerge. Now this made me a bit wary. I've had first hand expereince of programming a Word mailmerge and it wasn't a pleasant outcome. So the thought of doing a mailmerge in Word wasn't appealing. But it turns out that Aspose.Words for .Net has a single line API call that does the mailmerge for you. Brilliant!


But the second problem is a failing in Word 2007 - it doesn't support mailmerge with XML documents as a datasource. So I started looking at the examples that ship with Aspose.Words and stumbled on a Sales Invoice demo. In this case the Word document was using the NorthWinds Access database as the mailmerge source. In fact it was using 3 different views for the order header, the order line items and the order totals.

So how was I going to make that work with my XML source? A few minutes Googling gave me the answer. Word is simply using DataTables as the datasource so all I had to do was create a new DataTable with the same name as the one the Word document expected and create the appropriate columns with the correct data types. Then create a new row in the datatable and pass in the values extracted from the XML document. Bingo.

string Total = GetFieldFromXml(xmldoc, "eConnect/SOPTransactionType/taSopHdrIvcInsert/DOCAMNT");
// other strings declared and assigned here
ds.Tables[0].Rows.Add(OrderID, Subtotal, Freight, Total);

The order line items was easy to solve - I just created a DataRow for each node within my list of line items in the XML message.

What about creating the PDF document? Easy, just one line of code in Aspose.Words to specify that a PDF version is required and to open in the Web browser. I just did the usual trick of specifying the Response.ContentHeader to be application/pdf.

HttpResponse resp = Context.Response;
System.Text.Encoding enc = System.Text.Encoding.GetEncoding("ISO-8859-1");
resp.ContentEncoding = enc;
resp.ContentType = "application/pdf";
// now display PDF in browser
doc.Save("Aspose.Words.Demos.pdf", SaveFormat.Pdf, SaveType.OpenInBrowser, resp);

I was amazed how simple it was to create a PDF invoice. The great benefit of Aspose.Words is the use of the Word document as a template. It's a snip to modify the layout to get what you want. If you want to add extra fields you'll need to modify the views in Access to produce extra columns. No problem for me because I'm an old hand at Access but if you are unfamiliar with it then you might want to reconsider this option. But this is a great solution for my needs. Watch out though there is license cost to pay!


Bjorn Button said...

As you have probably seen now, there are a lot of great converters in the market today to convert xml to pdf. What is important now is to ensure that the converter you are using is safe and reputable.

Steve Johnson said...

Thank's for this useful information...