Getting a connected PocketPC's serial number/device ID from a desktop

I probably should have mentioned, this is an older Pocket PC. I don't know how upgradeable it is. I had to buy an upgrade CD from ebay to get it from PocketPC 2002 to 2003. HP doesn't provide upgrades for it anymore.

It's an iPaq H3950.

I believe KernelIoControl() worked also with PPC 2002 as well (don't remember as I used such devices a while ago :) )

But CeRapiInvoke() should work anyway. How have you compiled the code and what are the errors?

Well I guess I'm not sure where to begin with the second link. I guess the only way I can get RapiEx.dll is to compile it myself using the C code he provides, but I have no idea how to get it to compile. What kind of VS project do I need to create this as? Where do I put that section of code that he provides? I tried an MFC Smart Device DLL with no luck. I get two errors:

'IOCTL_HAL_GET_DEVICEID': undeclared identifier
'KernelIoControl': identifier not found

1) you need to create regular Win32 dll (under C++->Smart Device projects) that exports some symbols - namely the function you're going to call from the PC via CeRapiInvoke()

2) I assume you've got the OpenNETCF lib from here already: http://rapi.codeplex.com/

3) depending on which SDK version you're using, search in Include folder for IOCTL_HAL_GET_DEVICEID, eg in PocketPC SDK it is uniqueid.h

4) for KernelIoControl: http://msdn.microsoft.com/en-us/library/aa909165.aspx
and you get it as simple as that (assuming that coredll.dll is loaded - usually the case in 99%) - put it after all #include directives in your C/C++ dll code:

extern BOOL KernelIoControl(
  DWORD dwIoControlCode,
  LPVOID lpInBuf,
  DWORD nInBufSize,
  LPVOID lpOutBuf,
  DWORD nOutBufSize,
  LPDWORD lpBytesReturned
);

Ok cool, that seemed to compile without issue. So now, I would just put this DLL on the Pocket PC and from the desktop, I'd use the OpenNETCF's Invoke method?

yes. I'd advise to put the dll to \Windows on PDA and then yes, call it via Invoke on rapi object from desktop

and while we're on it, you probably need to do one additional thing to get it working:

(1) alter security policy on PDA: http://msdn.microsoft.com/en-us/library/bb416355.aspx

or

(2) sign the dll

it depends on the recent settings you have on your PDA, but usually WM6 has restricted RAPI by default

Okay, now it's time for me to sound like a total idiot... how do I access this provisioning XML file that contains the security policy? I don't know how to reference the existing one or apply any changes to it.

no worries, we're all ask questions :)

I suggest to do the following:

0. you said that your device is 2002, so such policies are not relevant there on iPaq H3950

1. in order to get some proof of concept and demonstrate that it works on recent devices (WM6 etc) you can use Remote tools (Registry Edit in particular) and change these values manually

2. alternatively, you can create Setup.dll and use registry API to do the same

3. in addition to #2, you can add xml file to your cab file so it is applied during the installation (see http://www.codeproject.com/KB/mobile/deploycertwithcode.aspx and similar). this sample is not 100% what you want, but it gives you the idea

I'm waiting for a Pocket PC 2003 upgrade for the iPaq to get here. Will that make it any easier to set up the security policies? I'm assuming it's something with the security on the device that's preventing my code from working. I put the RapiEx.dll file on the device in the Windows folder, and now I'm running code on the desktop (shown in the code section) to do the invoke. When it runs, the program crashes on the line where I do the actual invoke. The error is: "Value cannot be null. Parameter name: source"

Dim DeviceID As String = ""
 
Using cfRAPI As RAPI = New RAPI
    If Not cfRAPI.DevicePresent Then Exit Sub
 
    cfRAPI.Connect()
 
    If cfRAPI.Connected Then
        Dim outputBuffer() As Byte
        cfRAPI.Invoke("RapiEx", "CeGetDeviceID", New Byte() {}, outputBuffer)
 
        If outputBuffer Is Nothing Then
            sDeviceID = ""
        End If
 
        Dim PresetIDOffset As Int32 = BitConverter.ToInt32(outputBuffer, 4)
        Dim PlatformIDOffset As Int32 = BitConverter.ToInt32(outputBuffer, &HC)
        Dim PlatformIDSize As Int32 = BitConverter.ToInt32(outputBuffer, &H10)
 
        Dim sbID As New StringBuilder()
        sbID.Append([String].Format("{0:X8}-{1:X4}-{2:X4}-{3:X4}-", BitConverter.ToInt32(outputBuffer, PresetIDOffset), BitConverter.ToInt16(outputBuffer, PresetIDOffset + 4), BitConverter.ToInt16(outputBuffer, PresetIDOffset + 6), BitConverter.ToInt16(outputBuffer, PresetIDOffset + 8)))
 
        For i As Integer = PlatformIDOffset To PlatformIDOffset + (PlatformIDSize - 1)
            sbID.Append([String].Format("{0:X2}", outputBuffer(i)))
        Next i
 
        DeviceID = sbID.ToString()
    End If
End Using
                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:

ok, can you include RAPI project to your solution and debug it to see where exactly it fails?
it should be either from desktop side (something with RAPI or parameters or marshalling) or on PDA.
put messageboxes to PDA dll to see whether it passes 100% or fails somewhere

This is the exception text that I'm getting. I put messageboxes in the RapiEx.dll code but none of them came up, so I'm assuming it didn't even make it that far.


System.ArgumentNullException was unhandled
  Message="Value cannot be null.
Parameter name: source"
  ParamName="source"
  Source="mscorlib"
  StackTrace:
       at System.Runtime.InteropServices.Marshal.CopyToManaged(IntPtr source, Object destination, Int32 startIndex, Int32 length)
       at System.Runtime.InteropServices.Marshal.Copy(IntPtr source, Byte[] destination, Int32 startIndex, Int32 length)
       at OpenNETCF.Desktop.Communication.RAPI.Invoke(String DLLPath, String FunctionName, Byte[] InputData, Byte[]& OutputData)
       at HandHeldSync.frmHandheldInfo.frmHandheldInfo_Load(Object sender, EventArgs e) in C:\Projects\HandHeldSync\HandHeldSync\SyncHandheld\frmHandheldInfo.vb:line 26
       at System.EventHandler.Invoke(Object sender, EventArgs e)
       at System.Windows.Forms.Form.OnLoad(EventArgs e)
       at System.Windows.Forms.Form.OnCreateControl()
       at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       at System.Windows.Forms.Control.CreateControl()
       at System.Windows.Forms.Control.WmShowWindow(Message& m)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       at System.Windows.Forms.ContainerControl.WndProc(Message& m)
       at System.Windows.Forms.Form.WmShowWindow(Message& m)
       at System.Windows.Forms.Form.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.SafeNativeMethods.ShowWindow(HandleRef hWnd, Int32 nCmdShow)
       at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
       at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
       at System.Windows.Forms.Control.set_Visible(Boolean value)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(ApplicationContext context)
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
       at HandHeldSync.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()

looks like one of the parameters is wrong in Invoke call (presumably New Byte() {} - this should generate Null as you don't specify the size and any items in the byte array)

try to pass Nothing there

Ok, I changed the line to:

cfRAPI.Invoke("RapiEx", "CeGetDeviceID", Nothing, outputBuffer)

I get a slightly different error now... Null Reference Exception occurred in OpenNETCF.Desktop.Communication.dll:


System.NullReferenceException was unhandled
  Message="Object reference not set to an instance of an object."
  Source="OpenNETCF.Desktop.Communication"
  StackTrace:
       at OpenNETCF.Desktop.Communication.RAPI.Invoke(String DLLPath, String FunctionName, Byte[] InputData, Byte[]& OutputData)
       at HandHeldSync.frmHandheldInfo.frmHandheldInfo_Load(Object sender, EventArgs e) in C:\Projects\HandHeldSync\HandHeldSync\SyncHandheld\frmHandheldInfo.vb:line 26
       at System.EventHandler.Invoke(Object sender, EventArgs e)
       at System.Windows.Forms.Form.OnLoad(EventArgs e)
       at System.Windows.Forms.Form.OnCreateControl()
       at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       at System.Windows.Forms.Control.CreateControl()
       at System.Windows.Forms.Control.WmShowWindow(Message& m)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       at System.Windows.Forms.ContainerControl.WndProc(Message& m)
       at System.Windows.Forms.Form.WmShowWindow(Message& m)
       at System.Windows.Forms.Form.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.SafeNativeMethods.ShowWindow(HandleRef hWnd, Int32 nCmdShow)
       at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
       at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
       at System.Windows.Forms.Control.set_Visible(Boolean value)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(ApplicationContext context)
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
       at HandHeldSync.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()

Dim DeviceID As String = ""
 
Using cfRAPI As RAPI = New RAPI
    If Not cfRAPI.DevicePresent Then Exit Sub
 
    cfRAPI.Connect()
 
    If cfRAPI.Connected Then
        Dim outputBuffer() As Byte
        cfRAPI.Invoke("RapiEx", "CeGetDeviceID", Nothing, outputBuffer)
 
        If outputBuffer Is Nothing Then
            sDeviceID = ""
        End If
 
        Dim PresetIDOffset As Int32 = BitConverter.ToInt32(outputBuffer, 4)
        Dim PlatformIDOffset As Int32 = BitConverter.ToInt32(outputBuffer, &HC)
        Dim PlatformIDSize As Int32 = BitConverter.ToInt32(outputBuffer, &H10)
 
        Dim sbID As New StringBuilder()
        sbID.Append([String].Format("{0:X8}-{1:X4}-{2:X4}-{3:X4}-", BitConverter.ToInt32(outputBuffer, PresetIDOffset), BitConverter.ToInt16(outputBuffer, PresetIDOffset + 4), BitConverter.ToInt16(outputBuffer, PresetIDOffset + 6), BitConverter.ToInt16(outputBuffer, PresetIDOffset + 8)))
 
        For i As Integer = PlatformIDOffset To PlatformIDOffset + (PlatformIDSize - 1)
            sbID.Append([String].Format("{0:X2}", outputBuffer(i)))
        Next i
 
        DeviceID = sbID.ToString()
    End If
End Using

                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:

ok, that's how I used RAPI in one of the projects. it wasn't from OpenNETCF, but rather some home grown wrapper.

the bottom line is that the code in the snippet uses

<DllImport("rapi.dll", CharSet:=CharSet.Unicode, SetLastError:=True)> _
Public Shared Function CeRapiInvoke(ByVal dllPath As String, ByVal fnName As String, _
                                        ByVal cbInput As UInteger, ByVal pInput As IntPtr, _
                                        ByRef pcbOutput As UInteger, ByRef ppOutput As IntPtr, _
                                        ByVal res1 As Integer, ByVal res2 As Integer) As Integer
End Function

while OpenNETCF wrapper defines helper function as

public void Invoke(string DLLPath, string FunctionName, byte[] InputData, out byte[] OutputData)
{
}

and then uses InputData assuming it is NOT null.

P/Invoke declaration in OpenNETCF (converted from C# with http://www.developerfusion.com/tools/convert/csharp-to-vb/) is like that, ie practically the same as I used before:

<DllImport("rapi.dll", CharSet := CharSet.Unicode, SetLastError := True)> _
Friend Shared Function CeRapiInvoke(ByVal pDllPath As String, ByVal pFunctionName As String, ByVal cbInput As UInteger, ByVal pInput As IntPtr, ByRef pcbOutput As UInteger, ByRef ppOutput As IntPtr, _
ByVal ppIRAPIStream As IntPtr, ByVal dwReserved As UInteger) As Integer
End Function

Thus ensure that input buffer is not null and assigned some value, doesn't matter what, eg it can be 1 byte length with value = 0.

    Private Function IsDeviceSupported(ByRef errMsg As String) As Boolean
        Dim cbOutput As Integer
        Dim ppOutput As IntPtr
 
        Log("Checkig System Information...")
        Dim hr As Integer = Rapi.CeRapiInvoke("SetupDll.dll", "FnGetSystemInfo", 0, IntPtr.Zero, cbOutput, ppOutput, 0, 0)
        Dim logMsg As String = String.Format("hr = 0x{0:X}, LastError = 0x{1:X}, RapiLastError = 0x{2:X}", _
                    hr, Rapi.CeGetLastError(), Rapi.CeRapiGetError())
        Log(logMsg)
        If hr <> 0 Then
            If hr = NTE_BAD_SIGNATURE Then
                errMsg = "Unsupported device"
                Return False
            End If
            Dim errInfo As String = ""
            If cbOutput > 0 Then
                errInfo = Marshal.ReadInt32(ppOutput)
                Marshal.FreeCoTaskMem(ppOutput)
            Else
                errInfo = "No touchscreen driver is detected!"
            End If
            errMsg = "Unsupported device: " + errInfo
            Return False
        End If
        Return True
    End Function
                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:

So instead of:

   cfRAPI.Invoke("RapiEx", "CeGetDeviceID", Nothing, outputBuffer)

I should use:

   cfRAPI.Invoke("RapiEx", "CeGetDeviceID", New Byte() {0}, outputBuffer)

?

yep

It's still not working, I'm getting an Argument Null Exception is mscorlib.dll. It's complaining about the "source" parameter like it was before. I don't understand why it keeps complaining about this.

System.ArgumentNullException was unhandled
  Message="Value cannot be null.
Parameter name: source"
  ParamName="source"
  Source="mscorlib"
  StackTrace:
       at System.Runtime.InteropServices.Marshal.CopyToManaged(IntPtr source, Object destination, Int32 startIndex, Int32 length)
       at System.Runtime.InteropServices.Marshal.Copy(IntPtr source, Byte[] destination, Int32 startIndex, Int32 length)
       at OpenNETCF.Desktop.Communication.RAPI.Invoke(String DLLPath, String FunctionName, Byte[] InputData, Byte[]& OutputData)
       at HandHeldSync.frmHandheldInfo.frmHandheldInfo_Load(Object sender, EventArgs e) in C:\Projects\HandHeldSync\HandHeldSync\SyncHandheld\frmHandheldInfo.vb:line 33
       at System.EventHandler.Invoke(Object sender, EventArgs e)
       at System.Windows.Forms.Form.OnLoad(EventArgs e)
       at System.Windows.Forms.Form.OnCreateControl()
       at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       at System.Windows.Forms.Control.CreateControl()
       at System.Windows.Forms.Control.WmShowWindow(Message& m)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       at System.Windows.Forms.ContainerControl.WndProc(Message& m)
       at System.Windows.Forms.Form.WmShowWindow(Message& m)
       at System.Windows.Forms.Form.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.SafeNativeMethods.ShowWindow(HandleRef hWnd, Int32 nCmdShow)
       at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
       at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
       at System.Windows.Forms.Control.set_Visible(Boolean value)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(ApplicationContext context)
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
       at HandHeldSync.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()



I even created a completely new project that only attempts to get the device ID and it still is doing the same thing. I even created a C# project and used the same exact code from http://blog.opennetcf.com/ncowburn/2007/07/27/HOWTORetrieveTheDeviceIDFromTheDesktop.aspx (which didn't work). I changed the invoke line from "new byte[0] { }" to "new byte[] {0}"... I keep getting the same Argument Null Exception from mscorlib parameter "source"

ok, let's throw aside OpenNetCF for the moment, try attached wrapper.
it maybe less convenient but did the job for me :)

Looking at the OpenNETCF code behind the Invoke method, I see that it appears to be dying (around) here:

                  // copy the returned data from unmanaged to managed memory
                  Marshal.Copy(recvData, OutputData, 0, (int)recvSize);

recvData being the IntPtr that it's complaining about. So judging by the comment above the line and its location in the method's code, it looks like it's beyond the point where RapiEx.dll was invoked. A couple lines above it is:

                  // call the RAPI function
                  CeRapiInvoke(DLLPath, FunctionName, (uint)InputData.Length, sendData, out recvSize, out recvData, IntPtr.Zero, 0);

So does this mean that it's getting nothing back from CeGetDeviceID in my RapiEx.dll?

Ok, I'll try the wrapper you attached and I'll let you know what happens shortly. :)

Alright, that wrapper seems to work fine. The code below returns a number that I'd assume is the device ID. :)

I don't understand why OpenNETCF was being stupid, but since this wrapper seems to be doing exactly what I need/want it to do, I'll just use this instead.

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
 
        Dim i As Integer = Rapi.CeGetDeviceId()
        Label1.Text = i.ToString()
 
    End Sub
                                              

1:
2:
3:
4:
5:
6:

add messageboxes to RapiEx code to see it is indeed the same

Ok maybe I was wrong... Rapi.CeGetDeviceId returned a number at first, now it just returns -1. I have messageboxes in my RapiEx.dll but they never appeared.

The wrapper you provided me isn't supposed to reference RapiEx.dll, right?

I just tried it with another one of the PDAs I have and I get the same thing: The first time I click Button1, it returns a long number (I don't recall exactly what it returned but it was something like 184754553). Then if I click Button1 again, it returns -1.

Once it does that, even if I disconnect/reconnect the device, restart the program, it only returns -1 for that device.

Am I using the wrapper correctly?

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
 
        Dim i As Integer = Rapi.CeGetDeviceId()
        Label1.Text = i.ToString()
 
    End Sub
                                              

1:
2:
3:
4:
5:
6:

Err, correction: Physically disconnecting the device and reconnecting it will stop the -1 thing from happening. I get a different number though (this time it's 2039296204), so it's safe to assume I'm not using the wrapper correctly.

Clicking Button1 once more  though does cause -1 to be returned until I physically disconnect the device from my computer and reconnect it again.

ah, I've overlooked it in your earlier post - CeGetDeviceId() is NOT that the RapiEx did :)
it just gets the ID of connected device from PC's point of view.

you still need to use CeRapiInvoke() and check what happens

I'm not having a lot of luck here but I suspect it's in part because I've never done anything like this before. I revised Button1 and its code is listed below.

When I run the application and click on the button, nothing crashes but nothing appears to be coming back from RapiEx.dll. outputInt and outputIntPtr are both 0, but i comes back as -2147014795. The messageboxes that I've put in RapiEx.dll do not come up on the device. I tried changing the first parameter on my invoke line from "RapiEx.dll" to "\Windows\RapiEx.dll" just to make sure that wasn't the issue, but I get back the same values for outputInt, outputIntPtr, and i (0, 0, -2147014795 respectively).

I also wasn't sure if it was a signing issue. I had signed RapiEx.dll with a certificate I created on my certificate server. So I tried putting a copy of RapiEx.dll that I had not signed on the PDA and once again got the same results described above.

What I did next is take a different PDA (same model) and connect it. This PDA doesn't even have RapiEx.dll loaded on it. I ran my program, clicked button1, and again got the same exact values (i was -2147014795 again).

In my code for CeGetDeviceId in RapiEx.dll, the very first line is a messagebox... so if it's hitting that function at all, shouldn't that messagebox be appearing on the PDA's screen? I think given the fact that I'm not seeing a messagebox, and I'm getting the same values returned even on a PDA that doesn't even have RapiEx.dll on it, RapiEx.dll isn't being called at all.

This is how CeGetDeviceID starts in my RapiEx.dll:

int CeGetDeviceID(DWORD cbInput, BYTE *pInput, DWORD *pcbOutput, BYTE **ppOutput, PVOID pVoid)
{
      MessageBox(NULL, L"CeGetDeviceID", L"Test", MB_OK);

...

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
 
    Dim outputInt As Integer, outputIntPtr as IntPtr, i as Integer
 
    i = Rapi.CeRapiInvoke("RapiEx.dll", "CeGetDeviceID", 0, IntPtr.Zero, outputInt, outputIntPtr, 0, 0)
 
    MsgBox("i=" & i.ToString() & vbCrLf & "outputInt=" & outputInt.ToString() & vbCrLf & "outputIntPtr=" & outputIntPtr.ToString())
 
End Sub
                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:

before we continue, I do hope you've called CeRapiInit()

Oops. I wasn't. I added the following line just above the invoke line:

Dim init As Integer = Rapi.CeRapiInit()

I'm getting similar behavior. The value for i is coming back slightly different (now it's -2147467259). outputInt, outputIntPtr, and init are all 0.

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
 
    Dim outputInt As Integer, outputIntPtr as IntPtr, i as Integer
 
    Dim init As Integer = rapi.CeRapiInit()
    i = Rapi.CeRapiInvoke("RapiEx.dll", "CeGetDeviceID", 0, IntPtr.Zero, outputInt, outputIntPtr, 0, 0)
 
    MsgBox("i=" & i.ToString() & vbCrLf & "outputInt=" & outputInt.ToString() & vbCrLf & "outputIntPtr=" & outputIntPtr.ToString() & vbCrLf & "init=" & init.ToString())
 
End Sub
                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:

and init = 0 ?

it's a shame I don't have any 2002 device anymore, so we're mainly guessing now. And try OpenNETCF again, calling Connect() to initialise RAPI before you call Invoke()

Yes, init keeps returning 0. With OpenNETCF, I was already calling Connect().

The only other method I can think of is that I found a function specific to the iPAQ (which is what I'm using) that generates a file containing the device's asset information by running the asset export executable on the device.  I could read the serial number from there, but the problem is still getting the desktop to tell the device to do that.

Correct. No AV or firewall in the way.

I'll try the createprocess trick. That might be good enough to work for now until I can manage to get these devices updated to 2003.