Notes
A ColumnStyle to let you have a combobox column in a .NET DataGrid. The URL is the link where I lifted most of the code from. I fixed a couple of things like showing the DisplayMember not the value member when the item doesn't have focus + I made it so if you select something from the combo box then it makes that row of the DataGrid commit even if no other changes are made.
Associated URL
http://www.c-sharpcorner.com/winforms/ComboBoxInDataGridSKJ.asp