Retrieve all items from a SharePoint Field Choice Column

Answer 1

SPFieldMultiChoice and related fields have a Choices property:

SPFieldMultiChoice software = item.Fields[FieldNames.Software.Value()] as SPFieldMultiChoice;
StringCollection softwareChoices = software.Choices;

If you need to set a value on the field, use the SPFieldMultiChoiceValue type:

SPFieldMultiChoiceValue values = new SPFieldMultiChoiceValue();
values.Add("Choice 1");
values.Add("Choice 2");
item[FieldNames.Software.Value()] = values;