List<> convert to string[]

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

String[] convert to List<>

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

List<> convert to String

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

再添加个List<>去重复方法

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