其他-调整释放逻辑

PDF Office/ViewModels/MainContentViewModel.cs

@@ -166,8 +166,7 @@ namespace PDF_Office.ViewModels
         {
             if(PDFViewer!=null)
             {
-                PDFViewer.Document.Release();
-                //PDFViewer.CloseDocument();
+                PDFViewer.CloseDocument();
             }
         }