After running my silverlight 5.0 application with several PInvokes in it for 5 minutes or so, I get the following error:
Attempted to read or write protected memory
Likely, I'm getting a memory leak somewhere.
The problem is how do I debug this? I don't get a stacktrace at all so I can't pinpoint the offending code exactly.
By commenting out code and rerunning application several times, I think I managed to track down the problem but I can't figure out the problem.
Potentially Offending Code:
private void InitUSBEvents()
{
const string clsName = "SLUsbClass";
const string wndName = "SLUsbWindow";
Win32.WNDCLASSEX wndClassEx = new Win32.WNDCLASSEX();
wndClassEx.cbSize = Marshal.SizeOf(wndClassEx);
wndClassEx.lpszClassName = clsName;
wndClassEx.lpfnWndProc = WndProc;
rClassAtomValue = Win32.RegisterClassEx2(ref wndClassEx);
windowHandle = Win32.CreateWindowEx2(0, rClassAtomValue, wndName, 0, 0, 0, 0, 0, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);
Win32Usb.RegisterKeyboardUsbEvents(windowHandle);
}
[AllowReversePInvokeCalls]
private IntPtr WndProc(IntPtr hWnd, WM msg, IntPtr wParam, IntPtr lParam)
{
switch (msg)
{
case WM.INPUT:
//Console.WriteLine("Key Event");
break;
default:
return Win32.DefWindowProc(hWnd, msg, wParam, lParam);
}
return IntPtr.Zero;
}
PInvoke Related Declarations:
public class Win32
{
[DllImport("user32.dll", SetLastError = true, EntryPoint = "CreateWindowEx")]
public static extern IntPtr CreateWindowEx(
WindowStylesEx dwExStyle,
string lpClassName,
string lpWindowName,
WindowStyles dwStyle,
int x,
int y,
int nWidth,
int nHeight,
IntPtr hWndParent,
IntPtr hMenu,
IntPtr hInstance,
IntPtr lpParam);
// Create a window, but accept a atom value.
[DllImport("user32.dll", SetLastError = true, EntryPoint = "CreateWindowEx")]
public static extern IntPtr CreateWindowEx2(
WindowStylesEx dwExStyle,
UInt16 lpClassName,
string lpWindowName,
WindowStyles dwStyle,
int x,
int y,
int nWidth,
int nHeight,
IntPtr hWndParent,
IntPtr hMenu,
IntPtr hInstance,
IntPtr lpParam);
[DllImport("kernel32.dll", EntryPoint = "LocalAlloc")]
internal static extern IntPtr LocalAlloc_NoSafeHandle(
LocalMemoryFlags uFlags, IntPtr sizetdwBytes);
[DllImport("kernel32.dll", SetLastError = true)]
internal static extern IntPtr LocalFree(IntPtr hMem);
[DllImport("user32.dll", SetLastError = true, EntryPoint = "RegisterClassEx")]
public static extern UInt16 RegisterClassEx2([In] ref WNDCLASSEX lpwcx);
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.U2)]
public static extern short RegisterClassEx([In] ref WNDCLASSEX lpwcx);
[DllImport("user32.dll")]
public static extern IntPtr DefWindowProc(IntPtr hWnd, WM uMsg, IntPtr wParam, IntPtr lParam);
}
public class Win32Usb
{
public static bool RegisterKeyboardUsbEvents(IntPtr hWnd)
{
//Create an array of all the raw input devices we want to
//listen to. In this case, only keyboard devices.
//RIDEV_INPUTSINK determines that the window will continue
//to receive messages even when it doesn't have the focus.
RAWINPUTDEVICE[] rid = new RAWINPUTDEVICE[1];
rid[0].usUsagePage = 0x01;
rid[0].usUsage = 0x06;
rid[0].dwFlags = RIDEV_INPUTSINK;
rid[0].hwndTarget = hWnd;
return RegisterRawInputDevices(rid, (uint)rid.Length, (uint)Marshal.SizeOf(rid[0]));
}
[StructLayout(LayoutKind.Explicit)]
internal class RAWINPUT
{
[FieldOffset(0)]
public RAWINPUTHEADER header;
[FieldOffset(16)]
public RAWMOUSE mouse;
[FieldOffset(16)]
public RAWKEYBOARD keyboard;
[FieldOffset(16)]
public RAWHID hid;
}
[StructLayout(LayoutKind.Sequential)]
internal class RAWINPUTDEVICELIST
{
public IntPtr hDevice;
[MarshalAs(UnmanagedType.U4)]
public int dwType;
}
[StructLayout(LayoutKind.Sequential)]
internal struct RAWINPUTDEVICE
{
[MarshalAs(UnmanagedType.U2)]
public ushort usUsagePage;
[MarshalAs(UnmanagedType.U2)]
public ushort usUsage;
[MarshalAs(UnmanagedType.U4)]
public int dwFlags;
public IntPtr hwndTarget;
}
}
I can't really find anything wrong with the PInvoke declarations either. What are some good strategies to debug PInvoke related errors on Silverlight? Or is there a way to force the stacktrace to output? (I've tried turning on all exceptions to be thrown in Debug->Exception)