// create an array of string for adding
string[] items = new string[3] { "one", "two", "three" };
// add range of the string to the project list
project.Lists["List 1"].AddRange(items);
// create a list of string
List<string> list = new List<string> { "four", "five", "six" };
// add list of string to the project list
project.Lists["List 1"].AddRange(list);
// create an array of string for adding
$items = array( "one", "two", "three" );
// add range of the string to the project list
$project->Lists->get_Item("List 1")->AddRange($items);
// create a list of string
$list = new System\Collections\Generic\List<string> { "four", "five", "six" };
// add list of string to the project list
$project->Lists->get_Item("List 1")->AddRange($list);