获得textbox行数

            int EM_GETLINECOUNT = 0x00BA;//获取总行数的消息号
            int lc = SendMessage(this.textBoxHintMessage.Handle, EM_GETLINECOUNT, 0, 0);
            int sf = (this.textBoxHintMessage.Font.Height - 3) * lc;
            this.textBoxHintMessage.ClientSize = new Size(this.textBoxHintMessage.ClientSize.Width, sf);
            this.Size = new Size(textBoxHintMessage.Size.Width, sf + 23);

            labelTitle.Text = lc.ToString();
            //int count = 1;
            //string temp = "";
            //foreach (char ch in textBoxHintMessage.Text)
            //{
            //    temp += ch.ToString();
            //    Graphics g = textBoxHintMessage.CreateGraphics();
            //    SizeF sizef = g.MeasureString(temp, textBoxHintMessage.Font);
            //    if (sizef.Width > textBoxHintMessage.ClientSize.Width)
            //    {
            //        count++;
            //        temp = ch.ToString();
            //    }
            //}

            //labelTitle.Text = lc.ToString() + "    " + count.ToString();