Auto detect serial port using C#

Question

0.00/5 (No votes)

See more:

I am writing an application which automattically detects a modem plug to pc through usb_serial port.
Here is my code:

C#

[StructLayout(LayoutKind.Sequential)]
        public struct DEV_BROADCAST_PORT
        {
            public UInt32 dbcv_size;
            public UInt32 dbcv_devicetype;
            public UInt32 dbcv_reserved;
            public char dbcp_name;
        }


        protected override void WndProc(ref Message m)
        {
            const int WM_DEVICECHANGE = 0x0219;
            const int DBT_DEVICEARRIVAL = 0x8000;
            const int DBT_DEVICEREMOVECOMPLETE = 0x8004;
            const int DBT_DEVTYP_PORT = 0x00000003;
            switch (m.Msg)
            {
                case WM_DEVICECHANGE:
                    {
                        switch (m.WParam.ToInt32())
                        {
                            case DBT_DEVICEARRIVAL:
                                {
                                    int devType = Marshal.ReadInt32(m.LParam, 4);
                                    if (devType == DBT_DEVTYP_PORT)
                                    {
                                        DEV_BROADCAST_PORT _FTDI;
                                        _FTDI = (DEV_BROADCAST_PORT)Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_PORT));
                                        string port = Marshal.PtrToStringAuto((IntPtr)((long)m.LParam + 12));
                                    }
                                }
                                break;
                            case DBT_DEVICEREMOVECOMPLETE:
                                {
                                    int devType = Marshal.ReadInt32(m.LParam, 4);
                                    if (devType == DBT_DEVTYP_PORT)
                                    {
                                        DEV_BROADCAST_PORT _FTDI;
                                        _FTDI = (DEV_BROADCAST_PORT)Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_PORT));
                                        string port = Marshal.PtrToStringAuto((IntPtr)((long)m.LParam + 12));
                                    }
                                }
                                break;
                        }
                    }
                    break;
                default:
                    break;
            }

            base.WndProc(ref m);
        }

When i plug a modem to pc,it will create two serial port.And i wanna to find the comport which can send at command to modem.Anybody help me???
Thanks!!!!!!!!

Posted 13-Dec-12 22:15pm

congtk88

Updated 13-Dec-12 22:19pm

Krunal Rohit

v2

Add a Solution

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Answer 1 · 2012-12-13T22:18:00

Solution 1

You may use SerialPort.GetPortNames[^] method.

Posted 13-Dec-12 22:18pm

CPallini

Comments

congtk88 14-Dec-12 10:22am

when you use SerialPort.GetPortNames, it will return all comport on you PC. Problem is here that find the comport which i can send at command to modem.thanks!

Jibesh · Answer 2 · 2012-12-14T07:58:00

Here is sample code I solved when i faced a similar problem.

C#

using System.Management; // include this namespace

ConnectionOptions options = GetConnectionOptions();
ManagementScope connectionScope = GetConnectionScope(Environment.MachineName, options, @"\root\CIMV2");

ObjectQuery objectQuery = new ObjectQuery("SELECT * FROM Win32_PnPEntity WHERE ConfigManagerErrorCode = 0");
ManagementObjectSearcher comPortSearcher = new ManagementObjectSearcher(connectionScope, objectQuery);

using (comPortSearcher)
{
    string caption = null;
    foreach (ManagementObject obj in comPortSearcher.Get())
    {
        if (obj != null)
        {
          object captionObj = obj["Caption"];
          if (captionObj != null)
          {
             caption = captionObj.ToString();
             if (caption.Contains("(COM"))
             {
                COMPortInfo comPortInfo = new COMPortInfo();
                comPortInfo.Name = caption.Substring(caption.LastIndexOf("(COM")).Replace("(", string.Empty).Replace(")",
                                                                     string.Empty);
                comPortInfo.Description = caption;
                comPortInfoList.Add(comPortInfo);
              }
        }
   }
}
/EDIT
private static ManagementScope GetConnectionScope(string machineName, ConnectionOptions options, string path)
{
  ManagementScope connectScope = new ManagementScope();
  connectScope.Path = new ManagementPath(@"\\" + machineName + path);
  connectScope.Options = options;
  connectScope.Connect();
  return connectScope;
}

private static ConnectionOptions GetConnectionOptions(
{
    ConnectionOptions options = new ConnectionOptions();
    options.Impersonation = ImpersonationLevel.Impersonate;
    options.Authentication = AuthenticationLevel.Default;
    options.EnablePrivileges = true;
    return options;
}
/EDIT

In my application i make use of the Description property to identify my device. You may ignore the COMPortInfo class which is local class i used in my application. left the code just for better implementations..