winform进度条

参考资料：

http://www.cnblogs.com/zzy0471/archive/2010/12/12/1903602.html

http://www.cnblogs.com/haogj/archive/2012/12/13/2817047.html

https://www.dotnetperls.com/progressbar

https://www.cnblogs.com/tuzhiyuan/archive/2015/05/12/4497295.html

http://download.csdn.net/download/mirage1982/1023243