internal static MemoryStream GetFileContents(System.Windows.IDataObject dataObject, int index)
{
//cast the default IDataObject to a com IDataObject
IDataObject comDataObject;
comDataObject = (IDataObject)dataObject;
System.Windows.DataFormat Format = System.Windows.DataFormats.GetDataFormat("FileContents");
if (Format == null)
{
return(null);
}
FORMATETC formatetc = new FORMATETC();
formatetc.cfFormat = (short)Format.Id;
formatetc.dwAspect = DVASPECT.DVASPECT_CONTENT;
formatetc.lindex = index;
formatetc.tymed = TYMED.TYMED_ISTREAM | TYMED.TYMED_HGLOBAL;
//create STGMEDIUM to output request results into
STGMEDIUM medium = new STGMEDIUM();
//using the com IDataObject interface get the data using the defined FORMATETC
comDataObject.GetData(ref formatetc, out medium);
switch (medium.tymed)
{
case TYMED.TYMED_ISTREAM: return(GetIStream(medium));
default: throw new NotSupportedException();
}
}
/// <summary>
/// Sets managed data to a clipboard DataObject.
/// </summary>
/// <param name="dataObject">The DataObject to set the data on.</param>
/// <param name="format">The clipboard format.</param>
/// <param name="data">The data object.</param>
/// <remarks>
/// Because the underlying data store is not storing managed objects, but
/// unmanaged ones, this function provides intelligent conversion, allowing
/// you to set unmanaged data into the COM implemented IDataObject.</remarks>
public void SetDataEx(string format, object data)
{
System.Windows.DataFormat dataFormat = System.Windows.DataFormats.GetDataFormat(format);
// Initialize the format structure
FORMATETC formatETC = new FORMATETC
{
cfFormat = (short)dataFormat.Id,
dwAspect = DVASPECT.DVASPECT_CONTENT,
lindex = -1,
ptd = IntPtr.Zero
};
// Try to discover the TYMED from the format and data
TYMED tymed = GetCompatibleTymed(format, data);
// If a TYMED was found, we can use the system DataObject
// to convert our value for us.
if (tymed != TYMED.TYMED_NULL)
{
formatETC.tymed = tymed;
// Set data on an empty DataObject instance
System.Windows.DataObject conv = new System.Windows.DataObject();
conv.SetData(format, data, true);
// Now retrieve the data, using the COM interface.
// This will perform a managed to unmanaged conversion for us.
((IDataObject)conv).GetData(ref formatETC, out STGMEDIUM medium);
try
{
// Now set the data on our data object
SetData(ref formatETC, ref medium, true);
}
catch
{
// On exceptions, release the medium
ReleaseStgMedium(ref medium);
throw;
}
}
else
{
// Since we couldn't determine a TYMED, this data
// is likely custom managed data, and won't be used
// by unmanaged code, so we'll use our custom marshaling
// implemented by our COM IDataObject extensions.
SetManagedData(format, data);
}
}
