private void WritePropertySet()
{
Debug.Assert(0 < PropertyCount, "PropertyCount - zero size");
Debug.Assert(IntPtr.Zero != nativePropertySet, "ReadPropertySet - no memory");
Debug.Assert(currentPropertySetIndex < totalPropertySetCount, "WritePropertySet too far");
if ((currentPropertySetIndex < totalPropertySetCount) && (IntPtr.Zero != nativePropertySet)) // guard against memory overflow
{
int byteCount = PropertyCount * ODB.SizeOf_tagDBPROP;
IntPtr ptr = ADP.IntPtrOffset(nativePropertySet, currentPropertySetIndex * ODB.SizeOf_tagDBPROPSET);
try {
rgProperties = Marshal.AllocCoTaskMem(byteCount);
SafeNativeMethods.ZeroMemory(rgProperties, byteCount);
#if DEBUG
ODB.TraceData_Alloc(rgProperties, "DBPropSet - properties");
#endif
Marshal.WriteIntPtr(ptr, 0, rgProperties);
Marshal.WriteInt32(ptr, IntPtr.Size, cProperties);
IntPtr tmp = ADP.IntPtrOffset(ptr, IntPtr.Size + 4);
Marshal.StructureToPtr(guidPropertySet, tmp, false /*deleteold*/);
}
catch (Exception e) {
Marshal.WriteIntPtr(ptr, 0, IntPtr.Zero); // clear rgProperties
Marshal.WriteInt32(ptr, IntPtr.Size, 0); // clear cProperties
Marshal.FreeCoTaskMem(rgProperties); // FreeCoTaskMem protects itself from IntPtr.Zero
rgProperties = IntPtr.Zero;
cProperties = 0;
throw e;
}
currentPropertySetIndex++;
currentPropertyIndex = 0;
GC.KeepAlive(this);
}
}
