csharp:datagridview enter Half Width and Full Width characters

        /// <summary>
        /// 全角
        /// </summary>
        /// <param name="unicodeString"></param>
        /// <returns></returns>
        public static string FullWidthConvertor(string unicodeString)
        {

            StringBuilder sb = new StringBuilder(256);
            LCMapString(LOCALE_SYSTEM_DEFAULT, LCMAP_FULLWIDTH, unicodeString, -1, sb, sb.Capacity);
            return sb.ToString();

        }
        /// <summary>
        /// 半角
        /// </summary>
        /// <param name="unicodeString"></param>
        /// <returns></returns>
        public static string HalfWidthConvertor(string unicodeString)
        {

            StringBuilder sb = new StringBuilder(256);
            LCMapString(LOCALE_SYSTEM_DEFAULT, LCMAP_HALFWIDTH, unicodeString, -1, sb, sb.Capacity);
            return sb.ToString();

        }
        private const uint LCMAP_FULLWIDTH = 0x00800000;
        private const uint LOCALE_SYSTEM_DEFAULT = 0x0800;
        private const uint LCMAP_HALFWIDTH = 0x00400000;

        [DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
        public static extern int LCMapString(uint Locale, uint dwMapFlags, string lpSrcStr, int cchSrc, StringBuilder lpDestStr, int cchDest);

  /// <summary>
        /// DataGridView单位格输入全角转半角
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void dridViewRowNumberNo_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {
            GridViewRowNumberNo dt = sender as GridViewRowNumberNo;
            //获取列序号
            int columnIndex = dt.CurrentCell.ColumnIndex;
            //单位格转化成文本框
            TextBox tb = e.Control as TextBox;
            //委托单位格KeyPress事务
            tb.KeyPress += new KeyPressEventHandler(geovindu_KeyPress);
        }
        /// <summary>
        /// 单位格KeyPress事务
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void geovindu_KeyPress(object sender, KeyPressEventArgs e)
        {
            Control ctl = sender as Control;
            if (ctl == null)
                return;
            if (ctl.ImeMode != ImeMode.Hangul)
                ctl.ImeMode = ImeMode.Hangul;
            //全角转半角
            if (e.KeyChar >= 65296 && e.KeyChar <= 65305)
            {
                e.KeyChar -= Convert.ToChar(65248);
            }

        }