Can we install WebPart from 2010 on WebPart 2013?
I was write a webpart 2010, and now we prepere to migration on 2013. Can I install the same webpart from 2010 to 2013, or I must write a WebPart again ?
You can open the webpart which was created using VS 2010 in VS 2012 or 2013. You will need to update the assembly references, Dot Net framework version, reference to layouts, control templates etc. See here for more information on how to upgrade solutions created for SP 2010 t SP 2013 http://sharepointnadeem.blogspot.com/2013/12/sharepoint-2013-upgrade-sharepoint-2010.html