弄一个文本框，设置焦点到文本框那里，即可。

 通常，这个读卡器都是有开发文档的吧？

 你参考vb 和 vb.net 的代码去做。

 类似 http://www.foxtable.com/help/topics/2417.htm

【读写卡测试程序及源代码】 里面，不是有各自的例子么， c# 、 vb、 vb.net 都有有

网上找到一篇关于调用一款ID读卡器的API方法的文章，提到只需要两个dll文件就可以实现读卡器连接，具体如何操作，请各位老师指教，谢谢！！

此款ID读卡器提供两个dll文件：IDUSB.DLL、OUR_IDR.dll

========================================================

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace Attend
{
    public class IdCardHelper
    {
        /// <summary>
        /// 蜂鸣
        /// </summary>
        /// <param name="comport"></param>
        /// <returns></returns>
        [DllImport("OUR_IDR.dll")]
        public static extern byte idr_beep(UInt32 beepTime);

        /// <summary>
        /// 读卡，返回卡的信息
        /// </summary>
        /// <param name="comport"></param>
        /// <returns></returns>
        [DllImport("OUR_IDR.dll")]
        public static extern byte idr_read([MarshalAs(UnmanagedType.LPArray)] byte[] serial);

        /// <summary>
        /// 读卡，返回卡的信息
        /// </summary>
        /// <param name="comport"></param>
        /// <returns></returns>
        [DllImport("OUR_IDR.dll")]
        public static extern byte pcdgetdevicenumber([MarshalAs(UnmanagedType.LPArray)] byte[] devicenumbe);
    }
}

===============================================================================

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Attend
{
    public class CardOperate
    {
        /// <summary>
        /// 蜂鳴
        /// </summary>
        /// <param name="beepTime"></param>
        /// <returns></returns>
        public static byte DeviceBeep(UInt32 beepTime)
        {
            try
            {
                return IdCardHelper.idr_beep(beepTime);
            }
            catch
            {
                return 0;
            }
        }

        /// <summary>
        /// 讀取設備號
        /// </summary>
        /// <returns></returns>
        public static string DeviceRead()
        {
            try
            {
                string deviceNo = "";
                byte[] btDevice = new byte[4];
                byte readInfo = IdCardHelper.pcdgetdevicenumber(btDevice);

                for (int i = 0; i < btDevice.Length; i++)
                {
                    string strTemp = btDevice[i].ToString("x");
                    if (strTemp.Length == 1)
                        strTemp = "0" + strTemp;
                    deviceNo += strTemp;
                }
                return deviceNo;
            }
            catch
            {
                return null;
            }
        }

        /// <summary>
        /// 讀取卡號
        /// </summary>
        /// <returns></returns>
        public static string CardRead()
        {
            try
            {
                byte[] cardNo = new byte[5];
                byte readInfo = IdCardHelper.idr_read(cardNo);

                string strCard = "";
                for (int i = 0; i < cardNo.Length; i++)
                {
                    string strTemp = cardNo[i].ToString("x");
                    if (strTemp.Length == 1)
                        strTemp = "0" + strTemp;
                    strCard += strTemp;
                }
                strCard = strCard.Substring(2, 8);
                int intTemp = Convert.ToInt32(strCard, 16);
                strCard = intTemp.ToString();

                intTemp = strCard.Length;
                for (int i = 0; i < 10 - intTemp; i++)
                {
                    strCard = "0" + strCard;
                }

                //if (strCard == "0000000000")
                //{
                //    DeviceBeep(800);
                //}
                //else
                //{
                //    DeviceBeep(200);
                //}

                return strCard;
            }
            catch
            {
                return null;
            }
        }
    }
}