/// <summary>
        /// 根据文本内容设置textbox高度
        /// </summary>
        /// <param name="txt1"></param>
        private void SettxtHeight(TextBox txt1)
        {
            int txtHeight = 22;//设置单行的行高
            int MaxLineCount = 10;//设置最大行数
            Size size = TextRenderer.MeasureText(txt1.Text, textBox1.Font);
            int itxtLine = size.Width / txt1.Width +  txt1.Lines.Count()+ 1;
            if (itxtLine > MaxLineCount) { itxtLine = MaxLineCount; }
            txt1.Height = txtHeight * itxtLine;
        }