This property allows you to determine whether the the field
supports multiple values.
Most fields have a single value. A text box contains one item of
text. A radio button group has one selected button. A checkbox can
be checked or clear.
However, some kinds of fields can hold multiple values. For
example, a list box can be used to select multiple items. If this
is the case, then the MultiSelect property will be set to true.
If the field supports multiple selection, then the Value of the field will be a comma-delimited list
of the items which are selected.