protected void LoadDocument(IntPtr doc) { _document = doc; PdfiumLibrary.FPDF_GetDocPermissions(_document); _formCallbacks = new API.FPDF_FORMFILLINFO(); _formCallbacksHandle = GCHandle.Alloc(_formCallbacks, GCHandleType.Pinned); for (int i = 1; i <= 2; i++) { _formCallbacks.version = i; _form = PdfiumLibrary.FPDFDOC_InitFormFillEnvironment(_document, _formCallbacks); if (_form != IntPtr.Zero) { break; } } PdfiumLibrary.FPDF_SetFormFieldHighlightColor(_form, 0, 0xFFE4DD); PdfiumLibrary.FPDF_SetFormFieldHighlightAlpha(_form, 100); PdfiumLibrary.FORM_DoDocumentJSAction(_form); PdfiumLibrary.FORM_DoDocumentOpenAction(_form); Bookmarks = new PdfBookmarkCollection(); LoadBookmarks(Bookmarks, PdfiumLibrary.FPDFBookmark_GetFirstChild(_document, IntPtr.Zero)); }