Develop Reference

Windows UWP Bluetooh multiple devices showing for single device

I am currently working on a C#-UWP app that needs to be able to discovery bluetooth devices (Not BLE) on the network and ones that have been previously connected to/paired.
Im sure anyone who is new to this task will have quickly found the documentation and example are of little help. I have learned more from Stackoverflow questions about peoples experimentations than from the docs and examples, but anyways.
My main question/problem is this: After setting up the device watcher to find bluetooth devices I found that I consistently get multiple additions of the same device but having a different bluetooth address (this is a device that was previously paired but not live on the network). After much investigate and brainstorming, we discovered that each device id is actually a pairing of the devices MAC address and the BT receivers MAC address.
The reason I was getting 3 device additions per 1 physical device is because I have connected to that same device with 3 different BT receiver dongles in the past. So my question is, is there anyway to make the device watcher return the device that corresponds to the currently active BT receiver dongle?
Otherwise I will need to find the currently active BT receivers MAC address and filter out the devices that do not have this, because otherwise the user will see 3 identical devices to select and only 1 of them will pass while the other 2 will fail.
While on this subject I would also like to mention that the device properties dont seem to be working. Before creating the watcher, I have a list of properties like this for example:
requestedProperties.Add("System.Devices.Aep.DeviceAddress");
requestedProperties.Add("System.Devices.Aep.IsConnected");
requestedProperties.Add("System.Devices.Aep.Bluetooth.Le.IsConnectable");
requestedProperties.Add("System.Devices.Aep.IsPresent");
requestedProperties.Add("System.Devices.Aep.ContainerId");
requestedProperties.Add("System.Devices.Aep.ModelId");
requestedProperties.Add("System.Devices.Aep.Manufacturer");
requestedProperties.Add("System.Devices.Aep.ProtocolId");
requestedProperties.Add("System.Devices.Aep.SignalStrength");
But when I debug the device that is added, it doesnt have any properties:
debug info showing no properties for added device
I would be useful to have this information.
Thank you for any input or suggestions.

Update
I found a quick solution that overcomes this problem (although i did find a lot more problems with the device watcher but that is probably a topic for another question).
For now I simply get the current BT adaptors MAC address and then check each incoming device if it has this MAC address in its pair. If it does not that means the device is paired with an old/unused BT adaptor.
/* NOTE:
Windows allows only 1 BT adapter to be active on 1 machine at a time
Therefore this function will either return the active dongle or a null if
there is no BT adapter on the machine or its disabled.
*/
BluetoothAdapter BTAdaptor = await BluetoothAdapter.GetDefaultAsync();
if (BTAdaptor == null)
{
// Log error
// return
}
//
// Code block to check if the BT adaptor can support the BT tech stack you are interested in.
//
// Format into hex with 12 characters (12 being the number of characters for MAC address)
string tempMac = BTAdaptor.BluetoothAddress.ToString("X12").ToLower();
// Pattern for MAC address.
string pattern = "(.{2})(.{2})(.{2})(.{2})(.{2})(.{2})";
string replace = "$1:$2:$3:$4:$5:$6";
m_strBTAdapterMAC = Regex.Replace(tempMac, pattern, replace);
Then when the device is added/updated/removed by the watcher event, check it:
// If device is not paired with the currently used BT adapter.
if (deviceInfo.Id.Contains(m_strBTAdapterMAC) == false)
{
// Device paired with old dongle, dont want to show the user.
return;
}
If anyone ever figures out how to make the device watcher just not give old devices, please let me know, its probably a better solution.

Mapping Plug N Play Devices to PCI Slot IDs, C#

I have a certain number of external devices, let's call them Things.
Each Thing interfaces with the computer through a PnP Card plugged into a PCI slot.
Each Card has ports for 4 Things.
I need to obtain a UID for each Thing that persists and is consistent between reboots.
Note that the Things do not have a built in UID that I can access.
My idea to solve this problem is to get a UID for each port on the Cards. It seems to me that I just have to figure out which PCI slot each Card is plugged in to. That isn't going to change on reboot, and certainly the ports are going to be in the same order... so I can essentially label each port with the UID and know which UID each Thing is associated with.
I have done a fair bit of searching to figure out what C# objects would be of most use. The closest I have found is the ManagementObjectSearcher object from the System.Management library. Here is some simple code I wrote to see if this would get me what I want:
static void Main(string[] args)
{
IDsearch();
Console.ReadLine();
}
static void IDsearch()
{
ManagementObjectSearcher searcher =
new ManagementObjectSearcher("root\\CIMV2", "SELECT * FROM Win32_PnPEntity");
foreach (ManagementObject queryObj in searcher.Get())
{
Console.WriteLine("DeviceID: {0}", queryObj["DeviceID"]);
Console.WriteLine("Description: {0}", queryObj["Description"]);
}
}
This produces output like the following for every PnP devices on my computer:
DeviceID: ACPI\GENUINEINTEL_-_INTEL64_FAMILY_6_MODEL_60_-_INTEL(R)_CORE(TM)_I7-4790_CPU_#_3.60GHZ\_1
Description: Intel Processor
DeviceID: USB\VID_0CF3&PID_3004\ALASKA_DAY_2006
Description: Dell Wireless 1535C Bluetooth Device
This would fit my requirements if I could also obtain the PCI slot number.
I also came across the Win32_SystemSlot class, but this does not seem to give me a description of what is actually plugged into the slot! So at this point, I can get descriptions without PCI slots... and PCI slots without descriptions. I just can't map them together, which is what I need. I must be overlooking something or not asking the right question, because this strikes me as a pretty common thing.
Thank you for your help.

That sounds extremely fragile, what if the machine get moved and the devices get plugged into different ports. Is is a personal project or something you are trying to distribute. If the latter you should find another way. Are the "Things" of your own creation? If so you need to include the ability for each to have a unique identifier. If not you should contact the manufacturer and inquire. Trying to identify it by port may cause you lots of headaches down the road

I think you're looking for a combination of the Win32_Bus and the Win32_DeviceBus classes.
The Win32_Bus represents a physical bus as seen by a computer running a Windows operating system (Microsoft Docs). The bus type can be PCI and bus number seems to be an enumeration of the different physical PCI buses.
The Win32_DeviceBus relates a system bus and a logical device using the bus. This class is used to discover which devices are on which bus (Microsoft Docs). On my platform the device associated with a bus was always a Win32_PnPEntity.
Using these classes you should be able to find the physical bus attributes from a given Win32_PnPEntity.

Mac Id is coming same in 2 PCs while using C#

I have developed a software in C#, in which registration is done using mac id of PC as unique identifier. I registered the software on one PC using internet via usb tethering of my mobile, it took a mac id and got registered successfully. But when I tried to register on another PC using my mobile's internet via usb tethering, it is showing the same mac id which I got on registering first PC. I checked mac id of both PCs using ipconfig/all command in cmd and there same id is shown under physical address when my mobile is connected for internet. Why is this happening? What is the solution for this?
Code I used to fetch mac id:
string macAddresses = "", FinalmacAddresses = "";
foreach (NetworkInterface nic in NetworkInterface.GetAllNetworkInterfaces())
{
macAddresses = nic.GetPhysicalAddress().ToString();
break;
}
FinalmacAddresses = macAddresses.Trim().ToString();
return FinalmacAddresses;

First thing is, you should never use a mac address as a unique identifier. There are tools and even simple ways by which you can assign multiple devices with the same mac address (Mac address spoofing). That is also not good, if we look through the security perspective.
I would recommend using a GUID instead.

Obtaining the IP and MAC of client machines connecting to my ASP.NET MVC application on a server

I have just signed up because I need some clarification. I am an old man but a new graduate of a Systems Analysis college program and am on my first "real" job designing a system for a local company. Here is the deal. I am using ASP.NET MVC. Now, the company has assembly lines in a large manufacturing plant. Along the lines are stations where workers do a specific job on the line. The company has paper instructions that explain to the worker step by step how to do the job at their station. They want all this done electronically now....this is what I 'm doing.
So, when the leader of the assembly line starts their shift, they log into the system by opening up IE and connecting to the application server. From there, the leader picks a part to "make" on the line. The system then goes into the repository of instruction documents and retrieves all the documents needed by each station on the line to run the selected part. The system then needs to prepare the documents according to the station that will use them (ie. station 1 docs, station 2 docs,....etc). Then, the system needs to automatically open up the IE browser window on the client machine at each station on the line and display the login screen. The worker then logs onto the station and is presented with the "dashboard" screen with the instruction forms right there in front of him with buttons to navigate through the various docs for his station.
So now, we are wanting to have the system store the IP and Mac addresses of each station machine along each assembly line in a table along with fields that denote the assembly line and station # (ie. so a row in the table would have MAC | IP | ASSEMBLYLINE-ID | STATION-ID). This table will be populated before hand by admins so that the system knows already what the Mac and IP are for each machine on the floor. So, when the leader picks a part to run, the system can just check the machine the leader is logged into and get its MAC and IP and then look up in the table what line the machine is on. Then it can create a document queue for each station on the line, and then when the queues are ready, it can look in the table for the IP's of each machine on the line so that it can open the log on screen on the right machines.
However, it is possible that IP's may change from time to time. For this reason, we want to make sure we also use MAC addresses to validate the identity of a station machine whenever any communication needs to happen between the system and the clients. IP's alone just aren't good enough. Further, we are using all zero clients for this on the stations.
So, if you're still reading, lol. How can my system on the server, run a getMAC command on a machine that connects to it?

A web server cannot get the MAC address of a client machine. MAC addresses are stored on the physical ethernet layer and are not routed through socket connections. A MAC address stored in a packet is changed on every hop of a packet's journey. MAC is an abbreviation for Media Access Control, with "Media" referring to the local communication media. While source and destination IP-Addresses remain the same throughout the journey (and are used for long-distance routing decisions), the source and destination MAC-Addresses just indicate the next hop.
That being said, you can get the IP address like so:
Request.UserHostAddress()
However, as you yourself pointed out, this isn't reliable. Especially if the computers are behind a proxy or firewall.
To address your real problem, which is identifying a machine in your assembly line, one method is to get the computer name. You can open a command window and type the command hostname and that will return the computer name. It should be unique for each of your machines. If not, you can set it by right clicking on Computer. To get this name through javascript, use this code:
function GetComputerName()
{
try
{
var network = new ActiveXObject('WScript.Network');
var computerName = network.computerName;
return computerName;
}
catch (e) { }
return "";
}
Note that this code will only with with Internet Explorer and it may require you to enable special security settings inside the browser.

Fast replacement for Win32_NetworkAdapter WMI class for getting MAC address of local computer

TL;DR version of this question: WMI Win32_NetworkAdapter class contains information I need, but is too slow. What's a faster method of getting information for the MACAddress, ConfigManagerErrorCode, and PNPDeviceID columns on Windows?
I need to retrieve information for attached network adapters so I can get a MAC address to uniquely identify the local Microsoft Windows computer. The WMI Win32_NetworkAdapter class seems to have the information I'm looking for. The MACAddress, ConfigManagerErrorCode, and PNPDeviceID columns are the only ones I really need:
MACAddress: the MAC address (goal of this operation)
ConfigManagerErrorCode: allows me to determine if the adapter is enabled and running or not. (If it's disabled then I should use a MAC address previously cached by my app, if available).
PNPDeviceID: By checking for a prefix of "PCI" (and possibly other interfaces, if necessary) I can filter out non-physical adapters, of which there are several on my Windows 7 box (including virtual adapters, like for VMware / VirtualBox).
My plan was to filter out non-physical devices using PNPDeviceID. Then I would use the MACAddress column on any remaining table entries (saving the address to a cache). When the device is disabled (as possibly indicated by a non-zero ConfigManagerErrorCode) and the MACAddress is null, I can use a previously-seen MACAddress for that device from my cache.
You can see the contents of this table on my Windows 7 computer. You can see there's tons of junk in there, but only one entry with a "PCI" PNPDeviceID.
wmic:root\cli>NIC GET Caption, ConfigManagerErrorCode, MACAddress, PNPDeviceID
Caption ConfigManagerErrorCode MACAddress PNPDeviceID
[00000000] WAN Miniport (SSTP) 0 ROOT\MS_SSTPMINIPORT\0000
[00000001] WAN Miniport (IKEv2) 0 ROOT\MS_AGILEVPNMINIPORT\0000
[00000002] WAN Miniport (L2TP) 0 ROOT\MS_L2TPMINIPORT\0000
[00000003] WAN Miniport (PPTP) 0 ROOT\MS_PPTPMINIPORT\0000
[00000004] WAN Miniport (PPPOE) 0 ROOT\MS_PPPOEMINIPORT\0000
[00000005] WAN Miniport (IPv6) 0 ROOT\MS_NDISWANIPV6\0000
[00000006] WAN Miniport (Network Monitor) 0 ROOT\MS_NDISWANBH\0000
[00000007] Intel(R) 82567LM-2 Gigabit Network Connection 0 00:1C:C0:B0:C4:89 PCI\VEN_8086&DEV_10CC&SUBSYS_00008086&REV_00\3&33FD14CA&0&C8
[00000008] WAN Miniport (IP) 0 ROOT\MS_NDISWANIP\0000
[00000009] Microsoft ISATAP Adapter 0 ROOT\*ISATAP\0000
[00000010] RAS Async Adapter 0 20:41:53:59:4E:FF SW\{EEAB7790-C514-11D1-B42B-00805FC1270E}\ASYNCMAC
[00000011] Microsoft Teredo Tunneling Adapter 0 ROOT\*TEREDO\0000
[00000012] VirtualBox Bridged Networking Driver Miniport 0 00:1C:C0:B0:C4:89 ROOT\SUN_VBOXNETFLTMP\0000
[00000013] VirtualBox Host-Only Ethernet Adapter 0 08:00:27:00:C4:A1 ROOT\NET\0000
[00000014] Microsoft ISATAP Adapter 0 ROOT\*ISATAP\0001
[00000015] VMware Virtual Ethernet Adapter for VMnet1 0 00:50:56:C0:00:01 ROOT\VMWARE\0000
[00000016] Microsoft ISATAP Adapter 0 ROOT\*ISATAP\0002
[00000017] VMware Virtual Ethernet Adapter for VMnet8 0 00:50:56:C0:00:08 ROOT\VMWARE\0001
[00000018] Microsoft ISATAP Adapter 0 ROOT\*ISATAP\0003
(If I disable my physical adapter, then the MACAddress column goes to null, and ConfigManagerErrorCode changes to non-zero).
Unfortunately, this class is simply too slow. Any query on Win32_NetworkAdapter consistently takes 0.3 seconds on my relatively modern Windows 7 Core i7-based computer. So using this will add yet another 0.3 seconds to application startup (or worse), which I find unacceptable. This is especially because I can't think of a single valid reason why it should take so long to figure out what MAC addresses and plug-and-play device IDs are on the local computer.
Searching for other methods to get a MAC address yielded the GetAdaptersInfo and the newer GetAdaptersAddresses functions. They don't have the 0.3 second penalty that WMI imposes. These functions are the ones used by the .NET Framework's NetworkInterface class (as determined by examining .NET source code), and the "ipconfig" command line tool (as determined by using Dependency Walker).
I made a simple example in C# that lists all network adapters using the NetworkInterface class. Unfortunately, using these APIs seems to have two shortcomings:
These APIs don't even list disabled network adapters to begin with. That means I can't look up the MAC address for a disabled adapter from my cache.
I don't see how I can get the PNPDeviceID to filter out non-physical adapters.
My question is: what method can I use to get the MAC address of the local computer's physical adapters (whether it is enabled or not) in a few tens of milliseconds at most?
(I'm experienced at both C# and C++ and am fine with reading other languages, so I really don't care what language might be used in answers).
EDIT: In response to Alex K's suggestion for using return immediate and forward only, and also to provide some sample WMI code for what I am doing - here is some C# code that lists the columns of interest:
public static void NetTest() {
System.Diagnostics.Stopwatch sw = System.Diagnostics.Stopwatch.StartNew();
EnumerationOptions opt = new EnumerationOptions();
// WMI flag suggestions from Alex K:
opt.ReturnImmediately = true;
opt.Rewindable = false;
ManagementObjectSearcher searcher = new ManagementObjectSearcher("root\\cimv2", "select MACAddress, PNPDeviceID, ConfigManagerErrorCode from Win32_NetworkAdapter", opt);
foreach (ManagementObject obj in searcher.Get()) {
Console.WriteLine("=========================================");
foreach (PropertyData pd in obj.Properties) {
Console.WriteLine("{0} = {1}", pd.Name, pd.Value);
}
}
Console.WriteLine(sw.Elapsed.TotalSeconds);
}
I called this function 3 times and each time got about 0.36 seconds printed on the last line. So the suggested flags don't seem to have any effect: positive or negative. This is not too surprising, as the answer at How to make forward-only, read-only WMI queries in C#? seems to indicate that no change in performance will be observed unless there are a large number of records (e.g. hundreds to thousands), which is not the case with Win32_NetworkAdapter table.
EDIT 2: Multiple answers have been proposed to use SendARP from the IP helper API (this is the same API that has the GetAdaptersInfo function). What advantages does this give over GetAdaptersInfo for finding the local MAC address? I cannot think of any - on the surface, GetAdaptersInfo seems to return a more thorough set of information than SendARP does for local adapters. Now that I think about it, I think that a big part of my question centers over the concept of enumeration: what adapters exist on the computer in the first place? SendARP does not perform enumeration: it assumes you already know the IP address of the adapter you want a MAC for. I need to figure out what adapters exist on the system. Some issues this raises:
What happens if the network cable is unplugged? This would be very common on a laptop, for example (unplugged Ethernet, disconnected WiFi card). I tried using NetworkInterface.GetAllNetworkInterfaces() and listing all the unicast addresses using GetIPProperties().UnicastAddresses when the media is unplugged. No addresses are listed by Windows, so I can't think of any address that could be passed to SendARP. Intuitively, it makes sense that an unplugged adapter would still have a physical address, but no IP address (since it is not on a network with a DHCP server).
Which brings me to: how do I get a list of local IP addresses to test with SendARP?
How do I get the PNPDeviceID (or similar ID that can be used to filter non-physical adapters) for each adapter?
How do I list disabled adapters, so I can look up a MAC address from my cache (i.e. the MAC address I found when it was last enabled)?
These issues don't seem to be addressed by SendARP, and are the major reason I asked this question (otherwise I'd be using GetAdaptersInfo and moving on with things...).

I wound up cutting WMI completely out of the equation and made a significant improvement while still getting the information I wanted. As noted with WMI, it was taking > 0.30 seconds to get results. With my version, I can get the same information in about 0.01 seconds.
I used the setup API, configuration manager API, and then made OID requests directly on the NDIS network driver to get the MAC address. The setup API seems obnoxiously slow, especially when getting things like property values. It's imperative to keep setup API calls at a minimum. (You can actually see just how bad it is by looking at how long it takes to load the "Details" tab of a device in Device manager).
A guess on why WMI was so slow: I noted that WMI's Win32_NetworkAdapter always took the same amount of time no matter which subset of properties I queried. Seems like the WMI Win32_NetworkAdapter class programmers were lazy and didn't optimize their class to only gather requested information like other WMI classes do. They probably gather all information, whether requested or not. They probably significantly rely on Setup API to do this, and the excessive calls to the slow Setup API to get unwanted information is what makes it so slow.
High level overview of what I did:
Use SetupDiGetClassDevs to get all network devices that are present on the system.
I filter out all results that don't have an enumerator of "PCI" (use SetupDiGetDeviceRegistryProperty with SPDRP_ENUMERATOR_NAME to get the enumerator).
For the remainder, I can use CM_Get_DevNode_Status to get the device status and error code. All devices with removable device status codes are filtered out.
If DN_HAS_PROBLEM is set such that there is a non-zero error code then the device is probably disabled (or has some other problem). The driver isn't loaded so we can't make a request to the driver. Therefore in this case I load the MAC address for the network card from a cache I maintain.
A parent device could be removable so I filter those out too by recursively examining the device tree using CM_Get_Parent and CM_Get_DevNode_Status to look for parent removable devices.
Any remaining devices are nonremovable network cards on the PCI bus.
For each network device, I use SetupDiGetClassDevs with GUID_NDIS_LAN_CLASS GUID and DIGCF_DEVICEINTERFACE flag to get its interfaces (this only works if the device is enabled / does not have a problem).
Use IOCTL_NDIS_QUERY_GLOBAL_STATS with OID_802_3_PERMANENT_ADDRESS on the driver's interface to get the permanent MAC address. Save it in the cache, and then return.
The result is a robust indication of MAC addresses on the PC that should be immune to "fake" network cards made by VMware, VirtualBox, largely immune to network cards that are temporarily disabled, and immune to transient network cards attached via USB, ExpressCard, PC Card, or any future removable interface.
EDIT: IOCTL_NDIS_QUERY_GLOBAL_STATS isn't supported by all network cards. The vast majority work, but some Intel cards do not. See How to reliably and quickly get the MAC address of a network card given its device instance ID

You should be able to get everything you need from the System.Net namespace. For example, the following sample is lifted from MSDN and does what you asked for in the original version of the question. It displays the physical addresses of all interfaces on the local computer.
public static void ShowNetworkInterfaces()
{
IPGlobalProperties computerProperties = IPGlobalProperties.GetIPGlobalProperties();
NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
Console.WriteLine("Interface information for {0}.{1} ",
computerProperties.HostName, computerProperties.DomainName);
if (nics == null || nics.Length < 1)
{
Console.WriteLine(" No network interfaces found.");
return;
}
Console.WriteLine(" Number of interfaces .................... : {0}", nics.Length);
foreach (NetworkInterface adapter in nics)
{
IPInterfaceProperties properties = adapter.GetIPProperties(); // .GetIPInterfaceProperties();
Console.WriteLine();
Console.WriteLine(adapter.Description);
Console.WriteLine(String.Empty.PadLeft(adapter.Description.Length,'='));
Console.WriteLine(" Interface type .......................... : {0}", adapter.NetworkInterfaceType);
Console.Write(" Physical address ........................ : ");
PhysicalAddress address = adapter.GetPhysicalAddress();
byte[] bytes = address.GetAddressBytes();
for(int i = 0; i< bytes.Length; i++)
{
// Display the physical address in hexadecimal.
Console.Write("{0}", bytes[i].ToString("X2"));
// Insert a hyphen after each byte, unless we are at the end of the
// address.
if (i != bytes.Length -1)
{
Console.Write("-");
}
}
Console.WriteLine();
}
}