From 2be97bad853d9c70c9c67d23532cecb61c92bfe1 Mon Sep 17 00:00:00 2001
From: Dan Walmsley <dan@walms.co.uk>
Date: Mon, 30 Jan 2017 20:38:12 +0000
Subject: [PATCH] fixes null reference exception on gtk backend.

---
 src/Gtk/Avalonia.Gtk/SystemDialogImpl.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Gtk/Avalonia.Gtk/SystemDialogImpl.cs b/src/Gtk/Avalonia.Gtk/SystemDialogImpl.cs
index ed92a25873..962621856a 100644
--- a/src/Gtk/Avalonia.Gtk/SystemDialogImpl.cs
+++ b/src/Gtk/Avalonia.Gtk/SystemDialogImpl.cs
@@ -15,7 +15,7 @@ namespace Avalonia.Gtk
         public Task<string[]> ShowFileDialogAsync(FileDialog dialog, IWindowImpl parent)
         {
             var tcs = new TaskCompletionSource<string[]>();
-            var dlg = new global::Gtk.FileChooserDialog(dialog.Title, ((WindowImplBase)parent).Widget.Toplevel as Window, 
+            var dlg = new global::Gtk.FileChooserDialog(dialog.Title, ((WindowImplBase)parent)?.Widget.Toplevel as Window, 
                 dialog is OpenFileDialog
                     ? FileChooserAction.Open
                     : FileChooserAction.Save,
@@ -57,7 +57,7 @@ namespace Avalonia.Gtk
         public Task<string> ShowFolderDialogAsync(OpenFolderDialog dialog, IWindowImpl parent)
         {
             var tcs = new TaskCompletionSource<string>();
-            var dlg = new global::Gtk.FileChooserDialog(dialog.Title, ((WindowImplBase)parent).Widget.Toplevel as Window, 
+            var dlg = new global::Gtk.FileChooserDialog(dialog.Title, ((WindowImplBase)parent)?.Widget.Toplevel as Window, 
                 FileChooserAction.SelectFolder,
                 "Cancel", ResponseType.Cancel,
                 "Select Folder", ResponseType.Accept)