SwiftUI Table能否将选中项绑定至Item而非Item.ID？

核心思路是通过自定义Binding直接完成Table选中ID与协调器枚举的双向映射，省去中间的@State变量和onChange回调，逻辑更紧凑：

struct CollectionTable: View {
    
    @Environment(\.managedObjectContext) private var moc
    let collectionEntries: FetchedResults<CollectionEntry>
    @ObservedObject var coordinator = NavigationCoordinator.shared
    
    var body: some View {
        // 自定义双向绑定：将Table的ID选中集合与coordinator的枚举状态关联
        let selectionBinding = Binding<Set<CollectionEntry.ID>>(
            get: {
                // 从协调器当前状态反向获取选中ID集合
                guard case .entry(let entry) = coordinator.detailDisplay else {
                    return []
                }
                return [entry.id]
            },
            set: { newIDs in
                // 将选中ID转换为对应条目，同步到协调器
                if let id = newIDs.first,
                   let entry = collectionEntries.first(where: { $0.id == id }) {
                    coordinator.detailDisplay = .entry(entry)
                } else {
                    // 无选中项时重置状态（根据你的枚举定义调整case）
                    coordinator.detailDisplay = .none
                }
            }
        )
        
        Table(collectionEntries, selection: selectionBinding) {
            TableColumn("Name") { entry in
                Text(entry.name ?? "n/a")
            }
            TableColumn("Type") { entry in
                Text(entry.type ?? "n/a")
            }
            TableColumn("Language") { entry in
                Text(entry.lang ?? "n/a")
            }
            TableColumn("Price") { entry in
                Text(entry.price_usd.description ?? "n/a")
            }
            TableColumn("Count") { entry in
                Text(entry.count.description)
            }
        }
    }
}

优势 #

• 移除了冗余的@State private var selected变量，减少状态维护成本
• 无需额外的onChange监听，逻辑直接内聚在Binding中
• 支持双向同步：如果协调器的detailDisplay从外部被修改，Table的选中状态会自动同步更新

内容的提问来源于stack exchange，提问作者Stefan