As one can see every column of the grid has an associated data type. This means that every value in the same column will have the same type. If the user tries to change the value of a cell with a value whose type is incompatible with the type associated with the column, the value of the cell will not change. I also added some custom types, like Option and Strict Option. Data of this types are edited using combo boxes and drop down lists, as you can see in the next picture.
Every column has a type and a range for values.
This means that you can enter in the cells values that have the type associated with the column and are in the specified range. You can select multiple rows of the grid using right-click. Clicking the upper-left corner of the grid selects all rows in the grid. Double clicking the same area unselects all lines. From VB, for example, you can test if a row is selected or not.