SwiftUI Unknown Attribute 'Observable Object' - swiftui

Question

So I'm getting the error Unknown attribute ObservableObject next to the #ObservableObject var dataSource = DataSource() call below. the ObservableObject worked perfectly a couple days ago in another project but not anymore.
import SwiftUI
import Combine
class DataSource: ObservableObject {
var willChange = PassthroughSubject<Void,Never>()
var expenses = [Expense]() {
willSet { willChange.send() }
}
var savingsItems = [SavingsItem](){
willSet { willChange.send() }
}
//#State var monthlyIncomeText: String
//var monthlyIncome: Int = 1364
init(){
addNewExpense(withName: "Spotify", price: 14)
}
func addNewExpense(withName name: String, price: Int){
let newExpense = Expense(name: name, price: price)
expenses.append(newExpense)
}
func addNewSavingsItem(withName name: String, price: Int, percentage: Double){
let newSavingsItem = SavingsItem(name: name, price: price, timeTilCompletion: 0, percentage: percentage)
savingsItems.append(newSavingsItem)
}
}
struct ContentView: View {
#ObservableObject var dataSource = DataSource()
var body: some View {
VStack{
Text("Expenses")
List(dataSource.expenses) { expense in
ExpenseRow(expense: expense)
}
}
}
}
Could anyone help?

Answer 1

ObservableObject is a protocol that ObservedObjects must conform to. See here for documentation on ObservableObject, and here for documentation on ObservedObject, which is the property wrapper that you are looking for. Change your ContentView code to this:
struct ContentView: View {
#ObservedObject var dataSource = DataSource()
var body: some View {
VStack {
Text("Expenses")
List(dataSource.expenses) { expense in
ExpenseRow(expense: expense)
}
}
}
}