public Result <string> Ask()
{
IntPtr pidlRoot;
IntPtr hWndOwner;
if (mOwner is Window window)
{
var iw = new WindowInteropHelper(window);
hWndOwner = iw.Handle;
}
else if (mOwner is IWin32Window win32Window)
{
hWndOwner = win32Window.Handle;
}
else
{
hWndOwner = GetActiveWindow();
}
SHGetSpecialFolderLocation(hWndOwner, (int)mRoot, out pidlRoot);
if (pidlRoot == IntPtr.Zero)
{
return(Result.CreateError <Result <string> >("Error reading the root directory of the user profile. Perhaps there are no sufficient permissions to perform this action or the user profile is corrupted."));
}
var mergedOptions = mPublicOptions | mPrivateOptions;
if ((mergedOptions & (int)BrowseForFolderStyles.NewDialogStyle) != 0)
{
if (System.Threading.ApartmentState.MTA == System.Windows.Forms.Application.OleRequired())
{
mergedOptions = mergedOptions & ~(int)BrowseForFolderStyles.NewDialogStyle;
}
}
var pidlRet = IntPtr.Zero;
try
{
var bi = new BrowseForFolderDialogInfo();
var buffer = Marshal.AllocHGlobal(mMaxPathLength);
bi.pidlRoot = pidlRoot;
bi.hwndOwner = hWndOwner;
bi.pszDisplayName = buffer;
bi.lpszTitle = mPrompt;
bi.ulFlags = mergedOptions;
bi.lpfn = BrowseDialogCallback;
pidlRet = SHBrowseForFolder(ref bi);
Marshal.FreeHGlobal(buffer);
if (pidlRet == IntPtr.Zero)
{
return(Result.CreateError <Result <string> >(new OperationCanceledException()));
}
var sb = new StringBuilder(mMaxPathLength);
if (0 == SHGetPathFromIDList(pidlRet, sb))
{
return(Result.CreateError <Result <string> >(new OperationCanceledException()));
}
mPath = sb.ToString();
}
finally
{
IMalloc malloc;
SHGetMalloc(out malloc);
malloc.Free(pidlRoot);
if (pidlRet != IntPtr.Zero)
{
malloc.Free(pidlRet);
}
}
return(new Result <string>(mPath));
}
[DllImport("shell32.dll", CharSet = CharSet.Auto)] static extern IntPtr SHBrowseForFolder(ref BrowseForFolderDialogInfo bi);