C#

dtSource.Merge(dtTarget);
DataTable dtReturn = dtTarget.GetChanges();

To resolve this issue we contacted the Microsoft Support team and after a few days of email exchange, we got the following message: ”I think the root of the issue is that Merge does not change row state. If you create a dataset, then manually change a row value, then row state is tweaked and GetChanges() behaves as expected.”

CAN_SetClientParam(
        WORD        wParam,   //specifies kind of parameter
        DWORD       dwValue); //Event handle

internal delegate void YourDelegate();

internal static class NativeMethods
{
    [DllImport("canapi2.dll", EntryPoint="CAN_SetClientParam")]
    public static extern uint SetClientParam(
        ushort wParam,
        YourDelegate dwValue);
}

public class YourWrapper
{
    public event EventHandler YourEvent;

    private YourDelegate yourDelegate;
    private uint lastCallbackResult;

    public YourWrapper()
    {
        yourDelegate = new YourDelegate(OnYourDelegate);
    }

    public uint LastCallbackResult
    {
        get{ return lastCallbackResult; }
    }

    public void CallUnmanaged(ushort wParam)
    {
        lastCallbackResult = NativeMethods.SetClientParam(wParam, yourDelegate);
    }

    private void OnYourDelegate()
    {
        OnYourEvent(EventArgs.Empty);
    }
    protected virtual void OnYourEvent(EventArgs e)
    {
        EventHandler eh = YourEvent;
        if(eh != null)
            eh(this, e);
    }
}

BOOL manualReset = false;
HANDLE theEvent = CreateEvent(NULL, manualReset, false, _T("TheEvent"));

...

SetEvent(theEvent);

...

event EventHandler theEventTriggered;

...

theEventTriggered += SomeHandler;

...

// code in some thread...

EventWaitHandle theEvent = EventWaitHandle.OpenExisting("TheEvent");
theEvent.waitOne();
if (theEventTriggered != null)
{
    theEventTriggered();
}

new EventWaitHandle(false, EventResetMode.AutoReset, "TheEvent");

EventWaitHandle.OpenExisting("TheEvent");

/*** C# code ***/
[DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi, CharSet = CharSet.Auto)]
public static extern IntPtr CreateEvent
(
	IntPtr lpEventAttributes,
	bool bManualReset,
	bool bIntialState,
	string lpName
);

public delegate void DoHandler();

public void Foo()
{
  //Get an adress
  IntPtr EventsAdress = CreateEvent(IntPtr.Zero, false, false, "TheEvent");

  //Register Delegate with this Adress (PseudoCode)
  DoHandler doH = new DoHandler(MethodForEventAction);
  doH = (DoHandler)Marshal.GetDelegateForFunctionPointer(EventsAdress, typeof(DoHandler));
  // -> causes PROBLEM in Visual Studio: Invalid Pointer!

  //Give the adress to the C++ code
  SetClientParam(wParam, EventsAdress );
}

public void MethodForEventAction()
{
  Console.WriteLine("Event from DLL raised.");
}

/*** C++ code ***/
SetEvent(EventsAdress); //-> Console: "Event from DLL raised."

//In the application:
IntPtr  MsgReceivedEvent

MsgReceivedEvent = CreateEvent(IntPtr.Zero, false, false, "RcvEvent"); //Kernel32.dll with PInvoke
startRcv((uint)MsgReceivedEvent); //Call a C++ Method with PInvoke

//In a thread:
EventWaitHandle theEvent = EventWaitHandle.OpenExisting("RcvEvent");
while (!PendingCancel)
{
    if (theEvent.WaitOne(5000))
    {
        Log("EVENT RAISED!");
    }
}

//Somewhere in the C++-Code:
SetEvent(MsgReceivedEvent); //MsgReceivedEvent from startRcv(..)

fiaolle wrote:

It just selects the last occurrence of the word.