Is a class library, user control, and web control for .net, written in C#, for drawing 2D Line, Bar, and Pie Charts. It features full, detailed customization capabilities, but most options have defaults for ease of use.
sourceforge : https://sourceforge.net/projects/zedgraph/
piechart sample : https://github.com/discomurray/ZedGraph/blob/master/demo/ZedGraph.Demo/PieChartDemo.cs
codeproject : http://www.codeproject.com/Articles/5431/A-flexible-charting-library-for-NET
random color gen : http://www.codeproject.com/Tips/254057/Random-Color-Generator
Visual C# mschart.PieChart https://www.youtube.com/watch?v=JRNbx1mOBcs
origin - http://www.pipiscrew.com/?p=5912 net-zedgraph