c# - Error with using Bitmap class in project -

c# - Error with using Bitmap class in project -

hi trying split logic of simple wpf programme projects in .net. created project type class library. after tried utilize class bitmap in class of project validator find error "the type or namespace name 'bitmap' not found (are missing using directive or assembly reference?) c:\users\Микола\documents\visual studio 2013\projects\dragndrop\businesslogic\util.cs" how solve trouble?

p.s. sorry i'm started studing .net, , types of projects

using system; using system.collections.generic; using system.linq; using system.text; using system.threading.tasks; using system.drawing; namespace businesslogic { class util { public bitmap cropimage(bitmap img, rectangle croparea) { bitmap bmpimage = new bitmap(img); homecoming bmpimage.clone(croparea, bmpimage.pixelformat); } } }

open solution explorer. in project folder, right-click 'references'. click 'add reference'. in list, check system.drawing. assembly reference added project. combined using line have, compiler should not complain anymore.

c# .net bitmap