Can I get the source for the out-of-the-box web parts in SharePoint 2010?

Question

I'd like to take an existing web part and add some functionality. Can this be done? I figured out how to download the dwp for the webpart but this does not appear to have any source code in it.

UPDATE

As noted in my comment below, my end goal is to create a page that will be able to search only on columns specific to the content type selected. If someone has suggestions on how to approach this, please let me know.

Answer 1

You can certainly do this for Content Query Web Parts, but beware that some web parts might be sealed.

If you use ILSpy you can view the SharePoint Assemblies to gain understanding of how the OOTB web parts work.

Here's a link to ILSpy: http://wiki.sharpdevelop.net/ilspy.ashx

Here's a link to Andrew Connell's blogpost on extending the Content Query Web Part, as an example: http://www.andrewconnell.com/blog/archive/2008/02/18/Subclassing-the-Content-Query-Web-Part-Adding-Dynamic-Filtering.aspx

Answer 2

.dwp and .webpart files contains only definitions of webparts: assembly, class, title, etc. Actual webpart code is in the Microsoft.SharePoint and Mirosoft.Office.Servers assemblies.

Answer 3

So, to extend a webpart, you may be looking at extending the actual class. For this you want to inherit the webpart as a base class.

You can use Reflector to view the source code if you like, though, if possible you should inherit to extend not, just copy&paste code. This allows you to benefit from Microsoft's bug fixes.

EDIT: May 10, 2011

Use ILSpy per James' post now that Reflector costs $$$

Answer 4

Firstly look for the page/webpart/class you are interested in and work out which assembly it is coming from, you can then use a dissasembler tool (like .Net Reflector or ILSpy) to work out what the code is.

In some cases MS will obfuscate the code so you cannot do this, but in most cases it is a really useful way of seeing how MS does something and hence how you can architect a similar or related solution.