為了讓兩個範例程式碼都能在 Xcode 中預覽，我們需要為每個範例分別加入 PreviewProvider。這樣做可以幫助我們在開發過程中即時查看介面效果。以下是兩個範例分別加入預覽的完整程式碼：

範例一：基本 Form

import SwiftUI

struct ContentView: View {
    @State private var username: String = ""
    @State private var notificationsEnabled: Bool = false

    var body: some View {
        Form {
            TextField("使用者名稱", text: $username)
            Toggle("接收通知", isOn: $notificationsEnabled)
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

範例二：使用 Section 分組

import SwiftUI

struct SectionedFormView: View {
    @State private var username: String = ""
    @State private var notificationsEnabled: Bool = false

    var body: some View {
        Form {
            Section(header: Text("個人資料")) {
                TextField("使用者名稱", text: $username)
            }
            
            Section(header: Text("設定")) {
                Toggle("接收通知", isOn: $notificationsEnabled)
            }
        }
    }
}

struct SectionedFormView_Previews: PreviewProvider {
    static var previews: some View {
        SectionedFormView()
    }
}