private int WriteFileListToHGlobal(ref IntPtr hGlobal, IEnumerable <string> files)
{
if (!files?.Any() ?? false)
{
return(unchecked ((int)UnmanagedMethods.HRESULT.S_OK));
}
char[] filesStr = (string.Join("\0", files) + "\0\0").ToCharArray();
_DROPFILES df = new _DROPFILES();
df.pFiles = Marshal.SizeOf <_DROPFILES>();
df.fWide = true;
int required = (filesStr.Length * sizeof(char)) + Marshal.SizeOf <_DROPFILES>();
if (hGlobal == IntPtr.Zero)
{
hGlobal = UnmanagedMethods.GlobalAlloc(GMEM_MOVEABLE | GMEM_ZEROINIT, required);
}
long available = UnmanagedMethods.GlobalSize(hGlobal).ToInt64();
if (required > available)
{
return(STG_E_MEDIUMFULL);
}
IntPtr ptr = UnmanagedMethods.GlobalLock(hGlobal);
try
{
Marshal.StructureToPtr(df, ptr, false);
Marshal.Copy(filesStr, 0, ptr + Marshal.SizeOf <_DROPFILES>(), filesStr.Length);
return(unchecked ((int)UnmanagedMethods.HRESULT.S_OK));
}
finally
{
UnmanagedMethods.GlobalUnlock(hGlobal);
}
}
/// <summary>
/// Returns the data packed after the DROPFILES structure.
/// </summary>
/// <param name="dropHandle"></param>
/// <returns></returns>
internal static string GetData(IntPtr dropHandle)
{
IntPtr data = UnsafeNativeMethods.GlobalLock(dropHandle);
try
{
_DROPFILES df = (_DROPFILES)Marshal.PtrToStructure(data, typeof(_DROPFILES));
if (df.fWide != 0)
{
IntPtr pdata = new IntPtr((long)data + df.pFiles);
return(Marshal.PtrToStringUni(pdata));
}
}
finally
{
if (data != IntPtr.Zero)
{
UnsafeNativeMethods.GlobalUnLock(data);
}
}
return(null);
}