public static extern int SHGetSpecialFolderLocation(IntPtr hwnd, int csidl, out CoTaskMemSafeHandle ppidl);
private static extern HResult PropVariantToStringVectorAlloc(PropVariantSafeHandle propvar, out CoTaskMemSafeHandle pprgsz, out uint pcElem);
private unsafe bool RunDialogOld(IntPtr hWndOwner)
{
CoTaskMemSafeHandle listHandle;
Interop.Shell32.SHGetSpecialFolderLocation(hWndOwner, (int)rootFolder, out listHandle);
if (listHandle.IsInvalid)
{
Interop.Shell32.SHGetSpecialFolderLocation(hWndOwner, (int)Environment.SpecialFolder.Desktop, out listHandle);
if (listHandle.IsInvalid)
{
throw new InvalidOperationException(SR.FolderBrowserDialogNoRootFolder);
}
}
using (listHandle)
{
uint mergedOptions = Interop.Shell32.BrowseInfoFlags.BIF_NEWDIALOGSTYLE;
if (!showNewFolderButton)
{
mergedOptions |= Interop.Shell32.BrowseInfoFlags.BIF_NONEWFOLDERBUTTON;
}
// The SHBrowserForFolder dialog is OLE/COM based, and documented as only being safe to use under the STA
// threading model if the BIF_NEWDIALOGSTYLE flag has been requested (which we always do in mergedOptions
// above). So make sure OLE is initialized, and throw an exception if caller attempts to invoke dialog
// under the MTA threading model (...dialog does appear under MTA, but is totally non-functional).
if (Control.CheckForIllegalCrossThreadCalls && Application.OleRequired() != System.Threading.ApartmentState.STA)
{
throw new System.Threading.ThreadStateException(string.Format(SR.DebuggingExceptionOnly, SR.ThreadMustBeSTA));
}
var callback = new Interop.Shell32.BrowseCallbackProc(FolderBrowserDialog_BrowseCallbackProc);
char[] displayName = ArrayPool <char> .Shared.Rent(Interop.Kernel32.MAX_PATH + 1);
try
{
fixed(char *pDisplayName = displayName)
{
var bi = new Interop.Shell32.BROWSEINFO();
bi.pidlRoot = listHandle;
bi.hwndOwner = hWndOwner;
bi.pszDisplayName = pDisplayName;
bi.lpszTitle = descriptionText;
bi.ulFlags = mergedOptions;
bi.lpfn = callback;
bi.lParam = IntPtr.Zero;
bi.iImage = 0;
// Show the dialog
using (CoTaskMemSafeHandle browseHandle = Interop.Shell32.SHBrowseForFolderW(ref bi))
{
if (browseHandle.IsInvalid)
{
return(false);
}
// Retrieve the path from the IDList.
Interop.Shell32.SHGetPathFromIDListLongPath(browseHandle.DangerousGetHandle(), out selectedPath);
GC.KeepAlive(callback);
return(true);
}
}
}
finally
{
ArrayPool <char> .Shared.Return(displayName);
}
}
}
