/// <summary>
/// Returns the hash code of the object.
/// </summary>
/// <returns></returns>
public override int GetHashCode()
{
if (!hashValue.HasValue)
{
uint size = ShellNativeMethods.ILGetSize(PIDL);
if (size != 0)
{
byte[] pidlData = new byte[size];
Marshal.Copy(PIDL, pidlData, 0, (int)size);
byte[] hashData = ShellObject.hashProvider.ComputeHash(pidlData);
hashValue = BitConverter.ToInt32(hashData, 0);
}
else
{
hashValue = 0;
}
}
return(hashValue.Value);
}
/// <summary>
/// Builds the data for the CFSTR_SHELLIDLIST Drag and Clipboard data format from the
/// ShellObjects in the collection.
/// </summary>
/// <returns>A memory stream containing the drag/drop data.</returns>
public MemoryStream BuildShellIDList()
{
if (content.Count == 0)
{
throw new InvalidOperationException(LocalizedMessages.ShellObjectCollectionEmptyCollection);
}
MemoryStream mstream = new MemoryStream();
try
{
BinaryWriter bwriter = new BinaryWriter(mstream);
// number of IDLs to be written (shell objects + parent folder)
uint itemCount = (uint)(content.Count + 1);
// grab the object IDLs
IntPtr[] idls = new IntPtr[itemCount];
for (int index = 0; index < itemCount; index++)
{
if (index == 0)
{
// Because the ShellObjects passed in may be from anywhere, the
// parent folder reference must be the desktop.
idls[index] = ((ShellObject)KnownFolders.Desktop).PIDL;
}
else
{
idls[index] = content[index - 1].PIDL;
}
}
// calculate offset array (folder IDL + item IDLs)
uint[] offsets = new uint[itemCount + 1];
for (int index = 0; index < itemCount; index++)
{
if (index == 0)
{
// first offset equals size of CIDA header data
offsets[0] = (uint)(sizeof(uint) * (offsets.Length + 1));
}
else
{
offsets[index] = offsets[index - 1] + ShellNativeMethods.ILGetSize(idls[index - 1]);
}
}
// Fill out the CIDA header
//
// typedef struct _IDA {
// UINT cidl; // number of relative IDList
// UINT aoffset[1]; // [0]: folder IDList, [1]-[cidl]: item IDList
// } CIDA, * LPIDA;
//
bwriter.Write(content.Count);
foreach (uint offset in offsets)
{
bwriter.Write(offset);
}
// copy idls
foreach (IntPtr idl in idls)
{
byte[] data = new byte[ShellNativeMethods.ILGetSize(idl)];
Marshal.Copy(idl, data, 0, data.Length);
bwriter.Write(data, 0, data.Length);
}
}
catch
{
mstream.Dispose();
throw;
}
// return CIDA stream
return(mstream);
}
