how to do a join in .net service code example

Example: join in linq c#

IList<string> strList1 = new List<string>() { 
    "One", 
    "Two", 
    "Three", 
    "Four"
};

IList<string> strList2 = new List<string>() { 
    "One", 
    "Two", 
    "Five", 
    "Six"
};

var innerJoin = strList1.Join(strList2,
                      str1 => str1, 
                      str2 => str2, 
                      (str1, str2) => str1);