修正ObjectCollection错误的销毁导致的db为空

src/DatabaseServices/ObjectCollection.ts

@@ -60,19 +60,13 @@ export class ObjectCollection<T extends CADObject> extends CADObject
         }
     }
 
-    Destroy()
-    {
-        super.Destroy();
-        this.Objects.length = 0;
-    }
-
     //#region -----------------------------File-----------------------------
     //对象应该实现dataIn和DataOut的方法,为了对象的序列化和反序列化
 
     //对象从文件中读取数据,初始化自身
     ReadFile(file: CADFiler)
     {
-        this.Destroy();
+        this.Objects.length = 0;
         super.ReadFile(file);
         let cout = file.Read();
         this.Objects = [];