In the current cell key press event, I think this code will get the type of the column:
GridCurrentCell cc = e.TableControl.CurrentCell;
GridTableCellStyleInfo style = e.TableControl.Model[cc.RowIndex, cc.ColIndex];
if(style.TableCellIdentity.Column != null)
{
Type t = style.TableCellIdentity.Column.FieldDescriptor.GetPropertyType();
Console.WriteLine(t);
}
If you want to loop through all columns, you can loop through the grid.TableDescriptor.Columns collection using the column.FieldDescriptor.GetPropertyType() to get teh type of each column.