发布时间:2020-09-06编辑:佚名阅读(2878)
SerialPort.GetPortNames方法很好用,但当我们系统中存在虚拟串口时(部分蓝牙设备或者手机接上电脑后会虚拟出一些串口),此方法获取到的串口号可能就不是我们想要的结果了,如图:
对比图片红色标记区域会发现,.net提供的方法获取的串口号后面带有一个特殊字符,如果仅是特殊字符那还好说,过滤一下就好了,但你GOOGLE会发现,有不少朋友碰到过这样的问题,他们串口号后面多出的字符可能是字母,数字,或者跟我一样是特殊字符,后两种情况都还好说,但如果多出的是数字呢(例如“COM3”变成了“COM36”)?
起初我也只是过滤一下非数字,但在生产环境下什么情况都有可能发生,所以又改成了调用系统API读取注册表并处理读取结果的方案,以下为我的代码:
[DllImport("advapi32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)] private static extern int RegCloseKey(int hKey); [DllImport("advapi32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true, EntryPoint = "RegOpenKeyA")] private static extern int RegOpenKey(uint hKey, string lpSubKey, ref int phkResult); [DllImport("advapi32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true, EntryPoint = "RegEnumValueA")] private static extern int RegEnumValue(int hKey, int dwIndex, [MarshalAs(UnmanagedType.VBByRefStr)] ref string lpValueName, ref int lpcbValueName, int lpReserved, int lpType, [MarshalAs(UnmanagedType.VBByRefStr)] ref string lpData, ref int lpcbData); /// <summary> /// 获取当前计算机的串口名称数组 /// </summary> /// <returns></returns> public static string[] GetSerialPortNames() { #region 方式一:调用系统API(DLL文件:advapi32.dll)读取注册表,并处理读取结果的“字符串结束符” string[] ports = null; List<string> portsList = new List<string>(); uint HKEY_LOCAL_MACHINE = 0x80000002; int hKey = -1; int ret = RegOpenKey(HKEY_LOCAL_MACHINE, @"Hardware\DEVICEMAP\SERIALCOMM", ref hKey); try { if (ret == 0) { int index = 0; int BufferSize = 255; int ERROR_NO_MORE_ITEMS = 259; string valueName = "".PadRight(BufferSize, ' '); int valueNameLength = BufferSize; int valueLength = BufferSize; string value = "".PadRight(BufferSize, ' '); while (RegEnumValue(hKey, index, ref valueName, ref valueNameLength, 0, 0, ref value, ref valueLength) != ERROR_NO_MORE_ITEMS) { if (valueLength > 0) { if (value[valueLength - 1] == 0) valueLength -= 1; portsList.Add(value.Substring(0, valueLength)); } index += 1; valueName = "".PadRight(BufferSize, ' '); valueNameLength = BufferSize; valueLength = BufferSize; } } } catch (Exception) { } finally { if (ret == 0) RegCloseKey(hKey); } if (portsList.Count == 0) ports = new string[0]; else ports = portsList.ToArray(); return ports; #endregion #region 方式二:C#方式读取注册表后过滤非数字(此方式无法过滤数字,可能造成部分虚拟串口获取错误,例如 COM3 识别为 COM32) //HashSet<char> numbers = new HashSet<char>(new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' }); //string[] ports = null; //RegistryKey localMachine = null; //RegistryKey subKey = null; //new RegistryPermission(RegistryPermissionAccess.Read, @"HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM").Assert(); //try //{ // localMachine = Registry.LocalMachine; // subKey = localMachine.OpenSubKey(@"HARDWARE\DEVICEMAP\SERIALCOMM", false); // if (subKey != null) // { // string[] valueNames = subKey.GetValueNames(); // ports = new string[valueNames.Length]; // for (int j = 0; j < valueNames.Length; j++) // { // object obj = subKey.GetValue(valueNames[j]); // if (obj == null) // continue; // string str = (string)obj; // if (string.IsNullOrEmpty(str) || str.Length < 4) // continue; // string port = "COM"; // char[] cs = str.Substring(3).Replace("\n", "").ToCharArray(); // foreach (char c in cs) // { // if (numbers.Contains(c)) // port += c.ToString(); // else // break; // } // ports[j] = port; // } // } //} //finally //{ // if (localMachine != null) // localMachine.Close(); // if (subKey != null) // subKey.Close(); // System.Security.CodeAccessPermission.RevertAssert(); //} //if (ports == null) // ports = new string[0]; //return ports; #endregion }
关键字: C# SerialPort.GetPortNames() 获取串口号 错误
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