List<>与string[]以及List<>与string

List<string> list=new List<string>();
string str=list.ToArray();

string[] str={"str1","str2","str3"};
List<string> list=new List<string>(str);

List<string> list=new List<string>();
string str=String.Join(";",list.ToArray());

List<String> list=new List<string>();
list.Add("test1");
list.Add("test1");
list.Add("test2");
list.Add("test2");
System.Collections.Generic.HashSet<string> h = new System.Collections.Generic.HashSet<string>(list);
list.clear();
list.AddRange(h);