Merge branch 'develop' of git.kdan.cc:Mac_PDF/PDF_Office into develop

PDF Office/PDF Master/Class/PDFWindowController/Side/LeftSide/Outline/KMOutlineViewController.swift

@@ -540,10 +540,19 @@ extension KMOutlineViewController: KMBOTAOutlineViewDelegate {
             self.isLocalEvent = true
             
             let outlineItem: KMBOTAOutlineItem = self.BOTAOutlineView.outlineView.item(atRow:self.BOTAOutlineView.outlineView.selectedRow) as! KMBOTAOutlineItem
-            if outlineItem.outline.destination != nil {
-                self.listView.go(toTargetPoint: outlineItem.outline.destination.point, on: outlineItem.outline.destination.page() , at: .top)
-            } else if outlineItem.outline.action != nil {
-                self.listView.perform(outlineItem.outline.action)
+            
+            if outlineItem.outline.destination.page() != nil {
+                if outlineItem.outline.destination != nil {
+                    self.listView.go(toTargetPoint: outlineItem.outline.destination.point, on: outlineItem.outline.destination.page() , at: .top)
+                } else if outlineItem.outline.action != nil {
+                    self.listView.perform(outlineItem.outline.action)
+                }
+            } else {
+                let alter = NSAlert()
+                alter.alertStyle = NSAlert.Style.informational
+                alter.messageText = NSLocalizedString("The target page is invalid, please relocate it.", comment: "")
+                alter.addButton(withTitle: NSLocalizedString("OK", comment:""))
+                alter.beginSheetModal(for: self.view.window ?? NSWindow())
             }
         }
     }