Createing a grid like MSFlexGridLib

Question

hello,

 i have to create a inventory software but for creating a invoice form i need a grid like
1. press a on first colomn then show list of product and select item then come to grid and auto fill price then come to 3rd colomn then enter price press enter then come new row same as all row ,

and edit on mouse click

but in .net control grid not work like that i use many example or try to creating own control but i am not able to creating a like that
so plese give me some idea
or code

thanks