/// <summary>
/// Opens the compound file storage.
/// </summary>
/// <param name="pwcsName">The path to the compound file to create</param>
/// <param name="ppstg">(out) The IStorage representing this compound file</param>
/// <returns>True indicates it opened successfully. False indicates that the file
/// could not be found.</returns>
public bool OpenStorage(
string pwcsName,
STGM flags,
out IStorage ppstg)
{
if (!ValidateCompoundFileStorage(pwcsName))
{
ppstg = null;
return(false);
}
Ole32Storage.STGOPTIONS stgoptions = new Ole32Storage.STGOPTIONS();
stgoptions.usVersion = 1;
stgoptions.ulSectorSize = 4096;
Guid guidIStorage = typeof(IStorage).GUID;
int result = Ole32Storage.StgOpenStorageEx(
pwcsName,
flags,
STGFMT.STGFMT_DOCFILE,
0,
ref stgoptions,
IntPtr.Zero,
ref guidIStorage,
out ppstg);
if (result != HRESULT.S_OK)
{
Marshal.ThrowExceptionForHR(result);
}
return(true);
}
/// <summary>
/// Creates the compound file storage
/// </summary>
/// <param name="pwcsName">The path to the compound file to create</param>
/// <param name="ppstg">(out) The IStorage representing this compound file</param>
public void CreateStorage(
string pwcsName,
out IStorage ppstg)
{
Ole32Storage.STGOPTIONS stgoptions = new Ole32Storage.STGOPTIONS();
stgoptions.usVersion = 1;
stgoptions.ulSectorSize = 4096;
Guid guidIStorage = typeof(IStorage).GUID;
int result = Ole32Storage.StgCreateStorageEx(
pwcsName,
STGM.FAILIFTHERE | STGM.TRANSACTED |
STGM.READWRITE | STGM.SHARE_DENY_WRITE,
STGFMT.STGFMT_DOCFILE,
0,
ref stgoptions,
IntPtr.Zero,
ref guidIStorage,
out ppstg);
if (result != HRESULT.S_OK)
{
Marshal.ThrowExceptionForHR(result);
}
}
/// <summary>
/// Writes the clsid to this storage.
/// </summary>
/// <param name="guid">The guid representing the clsid</param>
private void WriteClsid(Guid guid)
{
try
{
Ole32Storage.WriteClassStg(storage, ref guid);
}
catch (COMException e)
{
ThrowStorageException(e);
}
}
/// <summary>
/// Reads the clsid from this storage
/// </summary>
/// <returns>The guid representing the clsid for this storage</returns>
private Guid ReadClsid()
{
Guid clsid = Guid.NewGuid();
try
{
Ole32Storage.ReadClassStg(storage, ref clsid);
}
catch (COMException e)
{
ThrowStorageException(e);
}
return(clsid);
}
/// <summary>
/// Validates that the path to the file is a valid Compound File.
/// Returns false if the file does not exist.
/// </summary>
/// <param name="path"></param>
private bool ValidateCompoundFileStorage(string storageName)
{
if (!File.Exists(storageName))
{
//throw new COMException("StorageName does not exist", STG_E.FILENOTFOUND ) ;
return(false);
}
else
{
int result = Ole32Storage.StgIsStorageFile(storageName);
if (result == HRESULT.S_FALSE)
{
Marshal.ThrowExceptionForHR(STG_E.INVALIDHEADER);
}
else if (result != HRESULT.S_OK)
{
Marshal.ThrowExceptionForHR(result);
}
}
return(true);
}
