Question

有两个实体Parent和Child，这是一对多关系。一个父母和多个孩子。

我使用EditMode删除Child数据，例如：

@ObservedObject private var db = CoreDataDB<Child>(predicate: "parent")

var body: some View {

    VStack {
        Form {

            Section(header: Text("Title")) {
                ForEach(db.loadDB(relatedTo: parent)) { child in

                    if self.editMode == .active {
                        ChildListCell(name: child.name, order: child.order)
                    } else {
                        ...
                    }
                }
                .onDelete(perform: self.db.deleting)   <--- How to update CoreData when delete occurs in this line
            }
        }
    }
}

deleting方法在另一个类中定义，例如：

public func deleting(at indexset: IndexSet) {

    CoreData.executeBlockAndCommit {

        for index in indexset {
            CoreData.stack.context.delete(self.fetchedObjects[index])
        }
    }
}

并且我还想在Parent发生时更新Child和onDelete实体的其他属性。怎么做？

感谢您的帮助。

Answer 1

这是可行的方法

Section(header: Text("Title")) {
    ForEach(db.loadDB(relatedTo: parent)) { child in

        if self.editMode == .active {
            ChildListCell(name: child.name, order: child.order)
        } else {
            ...
        }
    }
    .onDelete { indices in 
      // make other update here ...

      self.db.deleting(at: indices)

      // ... or here
    }
}

在ForEach中发生onDelete时如何更新其他CoreData？

1 个答案: