count sentence

Question

how we can count sentances in list ?
this is my code behind the button .
int count_sentence = 0;
string sentence = textBox2.Text;
ms_word_doc = sentence.Split('.').ToList();
count_sentence=(ms_word_doc);
textBox3.Text = textBox3.Text + Environment.NewLine + "the total no of sentences is " + count_sentence.ToString();