This should work:
List<string> test = new List<string>();
test.Add("test's");
test.Add("test");
test.Add("test's more");
string s = string.Join("','", test.Select(i => i.Replace("'", "''")));
And if you're really looking to enclose the whole thing in single quotes:
string s = string.Format("'{0}'", string.Join("','", test.Select(i => i.Replace("'", "''"))));
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…