string aaa = "你好123";
Label1.Text = aaa.Length.ToString(); //结果5
Label2.Text = System.Text.Encoding.Default.GetBytes(aaa).Length.ToString(); //结果7
string aaa = "你好123";
Label1.Text = aaa.Length.ToString(); //结果5
Label2.Text = System.Text.Encoding.Default.GetBytes(aaa).Length.ToString(); //结果7