add:PPT联动备用方法

Ink Canvas/Helpers/PPTManager.cs

@@ -519,6 +519,7 @@ namespace Ink_Canvas.Helpers
                             catch { }
                         }
                     }
+                }
 
                 PPTApplication = null;
                 CurrentPresentation = null;
@@ -564,7 +565,6 @@ namespace Ink_Canvas.Helpers
                     }
                 });
             }
-            }
             catch (Exception ex)
             {
                 LogHelper.WriteLogToFile($"断开PPT连接失败: {ex}", LogHelper.LogType.Error);