//弹出钱箱
        private void button4_Click(object sender, EventArgs e)
        {
            prnPort = txtport.Text.Trim();  //LPT1
            string str = TXT2.Text.Trim();
            IntPtr iHandle = CreateFile(prnPort, 0x40000000, 0, 0, OPEN_EXISTING, 0, 0);
            if (iHandle.ToInt32() == -1)
            {
                MessageBox.Show( "打开"+ prnPort + "失败");
            }
            else
            {
                //27,112,0,128,128
                FileStream fs = new FileStream(iHandle, FileAccess.ReadWrite);
                StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.Default);
                sw.Write(((char)27).ToString() + "p" + ((char)0).ToString() + ((char)128).ToString() + ((char)128).ToString());
               //   sw.Write(str);
                sw.Close();
                fs.Close();
                MessageBox.Show("执行成功！");
            }
        }

我正好有这个需求 。。搜索了一下。。改了一下。。我这个代码可以开我现在测试的钱箱。。 商务通收银机的。。。不同的钱箱有不同的代码