ZedGraph - .NET graph control
Today I needed a graphing control, and with a bit of searching found ZedGraph. This has got to be the best open source .NET component I’ve ever used. All you need to do is reference the .DLL, drop a ZedGraph control onto your form or control, and add some code to load in a data range. It’s even easier to make a pie chart and the colours, gradients, etc., are all customisable. Out of the box the control automatically has zooming, scaling, printing and exporting features accessible to the user, and it looks nice and clean. There’s also a ZedGraphWeb control built in which is for use in ASP.NET apps (although I haven’t tried that out).
There are two concurrent versions for both .NET 1.1 and .NET 2 (which is very handy since I’m limited to .NET 1.1 at work). The only difference between the versions is apparently use of templates for collections.
There’s a CodeProject article that gives a pile of simple demo code, and the main site is a Wiki with what looks like plenty of documentation. The library is licensed under the LGPL license, which means that derivative works must be LGPLed, but as long as the library’s DLLs are dynamically linked they can be included in commercial software.