CODEWITHSUNDEEP
c#
SaddamBinSyed
SaddamBinSyed

Reputation: 603

How to Pass Callback argument for Win32 Dll api from C# function?

  1. WIN32 funciton to call from C#:

    int PTSetGUICallbacks (  
  IN int hConnection,
  IN void *pGuiStreamingCallbackCtx,
  IN PT_GUI_STATE_CALLBACK pfnGuiStateCallback,
  IN void *pGuiStateCallbackCtx
)

  2. Win32 Callback function prototype "PT_GUI_STATE_CALLBACK": 

    int PT_STD_GUI_STATE_CALLBACK (
  IN DWORD dwGuiState,
  OUT BYTE *pbyResponse,
  IN DWORD dwMessage
)

  3. My C# function for to call the above Win32 function inside i am passing C# function as a callback to that Win32 function: 

    public void SetCallback() 
{
  var callback_delegate = new PT_GUI_STATE_CALLBACK(GUI_STATE_CALLBACK);            
  GCHandle gch = GCHandle.Alloc(callback_delegate);
  IntPtr intptr_delegate =
    Marshal.GetFunctionPointerForDelegate(callback_delegate);       
  int mErrorCode = PTSetGUICallbacks(mDevHandle, IntPtr.Zero, intptr_delegate,  IntPtr.Zero);       
  gch.Free(); 
 }

this code doesnot work, i mean i am not getting callback from win32 api to my C# method (GUI_STATE_CALLBACK)

So now i need to pass that callback to the win32 api from my C# function.

Anyone know the answer?

  1. PInvoke Function declaration for WIN32 api:

    public static extern int PTSetGUICallbacks(int ahConnection,
    IntPtr aStreamingcbCtx, IntPtr aGuiStateCb, IntPtr aGuiStateCbCtx);

Any update on this?

Is any other alternative way is there to do this?

Upvotes: 2

Views: 1620

Answers (1)

Marcel
Marcel

Reputation: 139

Define your CallBack function as "CallBack"

public static extern int PTSetGUICallbacks(
int ahConnection,IntPtr aStreamingcbCtx, 
CallBack aGuiStateCb, IntPtr aGuiStateCbCtx);

Calling it:

CallBack cb = new CallBack(GuiCBFunction);
PTSetGUICallbacks(mDevHandle, IntPtr.Zero, cb,  IntPtr.Zero);

The Callback in c#:

int GuiCBFunction (UInt32 dwGuiState, IntPtr pbyResponse, UInt32 dwMessage )

example for "CallBack": http://msdn.microsoft.com/de-de/library/a95009h1%28v=vs.80%29.aspx

Upvotes: 1

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