试试

try

string[] originText = { "Lorem ipsum dolor.", "Quisque at massa non erat.", "Donec auctor blandit nibh.", "Donec tincidunt." };
          var temp = originText.Select(k => k.Split(' ')[0]).GroupBy(k => k);
          Dictionary<string, int> dictCount = new Dictionary<string, int>();
          foreach (var item in temp)
              dictCount.Add(item.Key, item.Count());