protected override IntPtr HookProc(IntPtr hWnd, int msg, IntPtr wparam, IntPtr lparam)
{
if (msg == NativeMethods.WM_NOTIFY)
{
dialogHWnd = UnsafeNativeMethods.GetParent(new HandleRef(null, hWnd));
try {
UnsafeNativeMethods.OFNOTIFY notify = (UnsafeNativeMethods.OFNOTIFY)UnsafeNativeMethods.PtrToStructure(lparam, typeof(UnsafeNativeMethods.OFNOTIFY));
switch (notify.hdr_code)
{
case -601: /* CDN_INITDONE */
MoveToScreenCenter(dialogHWnd);
break;
case -602: /* CDN_SELCHANGE */
NativeMethods.OPENFILENAME_I ofn = (NativeMethods.OPENFILENAME_I)UnsafeNativeMethods.PtrToStructure(notify.lpOFN, typeof(NativeMethods.OPENFILENAME_I));
// Get the buffer size required to store the selected file names.
int sizeNeeded = (int)UnsafeNativeMethods.SendMessage(new HandleRef(this, dialogHWnd), 1124 /*CDM_GETSPEC*/, System.IntPtr.Zero, System.IntPtr.Zero);
if (sizeNeeded > ofn.nMaxFile)
{
// A bigger buffer is required.
try {
int newBufferSize = sizeNeeded + (FILEBUFSIZE / 4);
// Allocate new buffer
CharBuffer charBufferTmp = CharBuffer.CreateBuffer(newBufferSize);
IntPtr newBuffer = charBufferTmp.AllocCoTaskMem();
// Free old buffer
Marshal.FreeCoTaskMem(ofn.lpstrFile);
// Substitute buffer
ofn.lpstrFile = newBuffer;
ofn.nMaxFile = newBufferSize;
this.charBuffer = charBufferTmp;
Marshal.StructureToPtr(ofn, notify.lpOFN, true);
Marshal.StructureToPtr(notify, lparam, true);
}
catch {
// intentionaly not throwing here.
}
}
this.ignoreSecondFileOkNotification = false;
break;
case -604: /* CDN_SHAREVIOLATION */
// See VS Whidbey 95342. When the selected file is locked for writing,
// we get this notification followed by *two* CDN_FILEOK notifications.
this.ignoreSecondFileOkNotification = true; // We want to ignore the second CDN_FILEOK
this.okNotificationCount = 0; // to avoid a second prompt by PromptFileOverwrite.
break;
case -606: /* CDN_FILEOK */
if (this.ignoreSecondFileOkNotification)
{
// We got a CDN_SHAREVIOLATION notification and want to ignore the second CDN_FILEOK notification
if (this.okNotificationCount == 0)
{
this.okNotificationCount = 1; // This one is the first and is all right.
}
else
{
// This is the second CDN_FILEOK, so we want to ignore it.
this.ignoreSecondFileOkNotification = false;
UnsafeNativeMethods.SetWindowLong(new HandleRef(null, hWnd), 0, new HandleRef(null, NativeMethods.InvalidIntPtr));
return(NativeMethods.InvalidIntPtr);
}
}
if (!DoFileOk(notify.lpOFN))
{
UnsafeNativeMethods.SetWindowLong(new HandleRef(null, hWnd), 0, new HandleRef(null, NativeMethods.InvalidIntPtr));
return(NativeMethods.InvalidIntPtr);
}
break;
}
}
catch {
if (dialogHWnd != IntPtr.Zero)
{
UnsafeNativeMethods.EndDialog(new HandleRef(this, dialogHWnd), IntPtr.Zero);
}
throw;
}
}
return(IntPtr.Zero);
}