Merge branch 'dev' of http://git.kdan.cc:8865/Windows/PDFOffice_Windows_exe into dev

PDF Office/ViewModels/ViewContentViewModel.cs

@@ -2019,7 +2019,11 @@ namespace PDF_Master.ViewModels
                     //缩略图选中页面，要和当前显示的页面，一致
                     if (PDFViewer != null)
                     {
-                        events.GetEvent<PageEditSelectedItemEvent>().Publish(new PageEditSelectedItemEventArgs() { Unicode = unicode, SelectedItemIndex = PDFViewer.CurrentIndex });
+                        //防止部分情况PDFViewer.CurrentIndex获取异常问题
+                        if (PDFViewer.Document.PageCount > 0) 
+                        { 
+                            events.GetEvent<PageEditSelectedItemEvent>().Publish(new PageEditSelectedItemEventArgs() { Unicode = unicode, SelectedItemIndex = PDFViewer.CurrentIndex });
+                        }
                     }
 
                     #region part1