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Question

My sample app is getting crash while registering to Filechangeinfo notification

Answer 1

A:

SHChangeNotifyRegister is not declared properly, the code below returns successfully, not sure if I get a notification when I create a file though :)

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            SHChangeNotifyEntry changeEntry = new SHChangeNotifyEntry();

            changeEntry.dwEventMask = (uint)SHCNE.SHCNE_CREATE;
            changeEntry.Recursive = false;
            changeEntry.pszWatchDir = "\\My Documents\\";

            try
            {
                bool result = SHChangeNotifyRegister(this.Handle, ref changeEntry);
            }
            catch (Exception ee)
            {

            }
        }

        [DllImport("aygshell.dll")]
        private static extern bool SHChangeNotifyRegister(IntPtr hwnd, ref SHChangeNotifyEntry test);

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    struct SHChangeNotifyEntry
    {
        public uint dwEventMask;
        [MarshalAs(UnmanagedType.LPWStr)]
        public string pszWatchDir;
        public bool Recursive;
    }
}

Matt 2009-09-24 07:49:28

Thanks Matt..code worked.. i got notifications.. thank u..but you might have done some changes @ u have removed na..but at the very first what u have posted i am using.. its workin nicely :-).. thank u

Shadow 2009-09-24 09:37:10

Answer 2

A:

Hey Solitaire,

I need a similar event i.e. a event on file creation. I have made all changes said by Matt in the code you have posted, but I'm unable to receive events. The call is successfully completed, but on addition of a file wndproc does not receive event. Can you pls post your code after changes?

AgNO3 2010-04-21 11:12:43

For getting the file change notification in windows mobile, you need to, write the window proc in win32, handle "WM_FILECHANGEINFO" event. the sample application is provided in your windows mobile SDK folder check it. i have forgotten the name. if you want to use it in c#, you need to make the DLL in win32, use it in C#..the way to use in C# is provided in the above answer..if you have any problem ask me..

Shadow 2010-04-21 13:22:57

Answer 3

A:

I am developing the application in C#.Net CF. I have already implemented the wndproc. I receive paint events and others during form load. But when i add a file to the "\" folder which I'm monitoring, wndproc does not receive any events at all.

I have pasted the code below. I'm trying to monitor the root folder on Windows Mobile for file addition.

public delegate int WindowProcCallback(IntPtr hwnd, uint msg, uint wParam, uint lParam);


public partial class Form1 : Form
{
    [DllImport("coredll.dll")]
    public extern static int CallWindowProc(IntPtr lpPrevWndFunc, IntPtr hwnd, uint msg, uint wParam,
                                            uint lParam);

    [DllImport("coredll.dll")]
    public extern static IntPtr SetWindowLong(IntPtr hwnd, int nIndex,
                                              IntPtr dwNewLong);


    [DllImport("coredll.dll")]
    public static extern IntPtr GetWindowLong(IntPtr hWnd, int nIndex);

    private WindowProcCallback m_delegate;
    private IntPtr m_wndprocReal;

    const int GWL_WNDPROC = -4;
    public delegate int WindProc(IntPtr hWnd, int msg, IntPtr Wparam, IntPtr lparam); 

    public const uint WM_SHNOTIFY = 0x0401;

    private const int WM_FILECHANGEINFO = (0x8000 + 0x101);

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    struct SHChangeNotifyEntry
    {
        public uint dwEventMask;
        [MarshalAs(UnmanagedType.LPWStr)]
        public string pszWatchDir;
        public bool Recursive;
    }      


    [DllImport("aygshell.dll")]
    private static extern bool SHChangeNotifyRegister(IntPtr hwnd, ref SHChangeNotifyEntry test);

    public enum SHCNE : uint
    {
        SHCNE_RENAMEITEM = 0x00000001,
        SHCNE_CREATE = 0x00000002,
        SHCNE_DELETE = 0x00000004,
        SHCNE_MKDIR = 0x00000008,
        SHCNE_RMDIR = 0x00000010,
        SHCNE_MEDIAINSERTED = 0x00000020,
        SHCNE_MEDIAREMOVED = 0x00000040,
        SHCNE_DRIVEREMOVED = 0x00000080,
        SHCNE_DRIVEADD = 0x00000100,
        SHCNE_NETSHARE = 0x00000200,
        SHCNE_NETUNSHARE = 0x00000400,
        SHCNE_ATTRIBUTES = 0x00000800,
        SHCNE_UPDATEDIR = 0x00001000,
        SHCNE_UPDATEITEM = 0x00002000,
        SHCNE_SERVERDISCONNECT = 0x00004000,
        SHCNE_UPDATEIMAGE = 0x00008000,
        SHCNE_DRIVEADDGUI = 0x00010000,
        SHCNE_RENAMEFOLDER = 0x00020000,
        SHCNE_FREESPACE = 0x00040000,
        SHCNE_EXTENDED_EVENT = 0x04000000,
        SHCNE_ASSOCCHANGED = 0x08000000,
        SHCNE_DISKEVENTS = 0x0002381F,
        SHCNE_GLOBALEVENTS = 0x0C0581E0,
        SHCNE_ALLEVENTS = 0x7FFFFFFF,
        SHCNE_INTERRUPT = 0x80000000,
    }


    public Form1()
    {
        InitializeComponent();

        m_delegate = new WindowProcCallback(this.WnProc);
        m_wndprocReal = SetWindowLong(this.Handle, GWL_WNDPROC, Marshal.GetFunctionPointerForDelegate(m_delegate));

        SHChangeNotifyEntry changeEntry = new SHChangeNotifyEntry();

        changeEntry.dwEventMask = (uint)SHCNE.SHCNE_CREATE;
        changeEntry.Recursive = false;
        changeEntry.pszWatchDir = "\\";           

        try
        {
            bool result = SHChangeNotifyRegister(this.Handle, ref changeEntry);

        }
        catch (Exception ee)
        {

        }

    }

    private int WnProc(IntPtr hwnd, uint msg, uint wParam, uint lParam)
    {
        int ret = 0;

        if (msg != WM_FILECHANGEINFO)
            ret = CallWindowProc(m_wndprocReal, hwnd, msg, wParam, lParam);
        else
        {

        }

        return ret;
    }

}

Will appreciate your help.

Thanks.

AgNO3 2010-04-22 07:01:54

Did you get the sample example present in your windows mobile SDK..there they register for WM_DEVICE change Event.. just make a DLL, and call your .net binary from the DLL..it is not possible to register for filechange event in C#..

Shadow 2010-04-22 07:20:14

No. I did not get it. If it cannot be achieved n C#, then what does your code mentioned above in this post do? Can you provide an explanation? I thought it is for the same purpose.

AgNO3 2010-04-22 09:05:29

the code which is present above is for how to receive the window proc event from an win32 DLL.. my code was present in DLL, dll was getting the notification.. it inturn passing the message to C#..you see the sample app File Change Notification present in SDK,follow up this link "http://msdn.microsoft.com/en-us/library/bb158663.aspx" its in win32.. itself..make it DLL and register your c# app handle in C++ and pass the same event which you recive in win32 DLL to C# app..

Shadow 2010-04-22 10:27:18

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My sample app is getting crash while registering to Filechangeinfo notification

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