/// <include file='doc\DataObject.uex' path='docs/doc[@for="DataObject.OleConverter.GetDataFromOleIStream"]/*' />
/// <devdoc>
/// Uses IStream and retrieves the specified format from the bound IComDataObject.
/// </devdoc>
/// <internalonly/>
private Object GetDataFromOleIStream(string format) {
FORMATETC formatetc = new FORMATETC();
STGMEDIUM medium = new STGMEDIUM();
formatetc.cfFormat = unchecked((short)(ushort)(DataFormats.GetFormat(format).Id));
formatetc.dwAspect = DVASPECT.DVASPECT_CONTENT;
formatetc.lindex = -1;
formatetc.tymed = TYMED.TYMED_ISTREAM;
medium.tymed = TYMED.TYMED_ISTREAM;
// Limit the # of exceptions we may throw below.
if (NativeMethods.S_OK != QueryGetDataUnsafe(ref formatetc)){
return null;
}
try {
IntSecurity.UnmanagedCode.Assert();
try {
innerData.GetData(ref formatetc, out medium);
}
finally {
CodeAccessPermission.RevertAssert();
}
}
catch {
return null;
}
if (medium.unionmember != IntPtr.Zero) {
UnsafeNativeMethods.IStream pStream = (UnsafeNativeMethods.IStream)Marshal.GetObjectForIUnknown(medium.unionmember);
Marshal.Release(medium.unionmember);
NativeMethods.STATSTG sstg = new NativeMethods.STATSTG();
pStream.Stat(sstg, NativeMethods.STATFLAG_DEFAULT );
int size = (int)sstg.cbSize;
IntPtr hglobal = UnsafeNativeMethods.GlobalAlloc(NativeMethods.GMEM_MOVEABLE
| NativeMethods.GMEM_DDESHARE
| NativeMethods.GMEM_ZEROINIT,
size);
IntPtr ptr = UnsafeNativeMethods.GlobalLock(new HandleRef(innerData, hglobal));
pStream.Read(ptr, size);
UnsafeNativeMethods.GlobalUnlock(new HandleRef(innerData, hglobal));
return GetDataFromHGLOBLAL(format, hglobal);
}
return null;
}
internal State RefreshStorage(UnsafeNativeMethods.IPersistStorage iPersistStorage) {
Debug.Assert(storage != null, "how can we not have a storage object?");
Debug.Assert(iLockBytes != null, "how can we have a storage w/o ILockBytes?");
if (storage == null || iLockBytes == null) return null;
iPersistStorage.Save(storage, true);
storage.Commit(0);
iPersistStorage.HandsOffStorage();
try {
buffer = null;
ms = null;
NativeMethods.STATSTG stat = new NativeMethods.STATSTG();
iLockBytes.Stat(stat, NativeMethods.Ole.STATFLAG_NONAME);
length = (int) stat.cbSize;
buffer = new byte[length];
IntPtr hglobal = UnsafeNativeMethods.GetHGlobalFromILockBytes(iLockBytes);
IntPtr pointer = UnsafeNativeMethods.GlobalLock(new HandleRef(null, hglobal));
try {
if (pointer != IntPtr.Zero) {
Marshal.Copy(pointer, buffer, 0, length);
}
else {
length = 0;
buffer = null;
}
}
finally {
UnsafeNativeMethods.GlobalUnlock(new HandleRef(null, hglobal));
}
}
finally {
iPersistStorage.SaveCompleted(storage);
}
return this;
}