# ObservedObject A property wrapper type that subscribes to an observable object and invalidates a view whenever the observable object changes. ``` @MainActor @propertyWrapper @preconcurrency @frozen struct ObservedObject where ObjectType : ObservableObject ``` ## Overview Add the `@ObservedObject` attribute to a parameter of a SwiftUI [`View`](/documentation/SwiftUI/View) when the input is an and you want the view to update when the object’s published properties change. You typically do this to pass a [`StateObject`](/documentation/SwiftUI/StateObject) into a subview. The following example defines a data model as an observable object, instantiates the model in a view as a state object, and then passes the instance to a subview as an observed object: ``` class DataModel: ObservableObject { @Published var name = "Some Name" @Published var isEnabled = false } struct MyView: View { @StateObject private var model = DataModel() var body: some View { Text(model.name) MySubView(model: model) } } struct MySubView: View { @ObservedObject var model: DataModel var body: some View { Toggle("Enabled", isOn: $model.isEnabled) } } ``` When any published property of the observable object changes, SwiftUI updates any view that depends on the object. Subviews can also make updates to the model properties, like the [`Toggle`](/documentation/SwiftUI/Toggle) in the above example, that propagate to other observers throughout the view hierarchy. Don’t specify a default or initial value for the observed object. Use the attribute only for a property that acts as an input for a view, as in the above example. > Note: Don’t wrap objects conforming to the > > protocol with `@ObservedObject`. SwiftUI automatically tracks dependencies > to `Observable` objects used within body and updates dependent views when > their data changes. Attempting to wrap an `Observable` object with > `@ObservedObject` may cause a compiler error, because it requires that its > wrapped object to conform to the > > protocol. > > If the view needs a binding to a property of an `Observable` object in > its body, wrap the object with the ``doc://com.apple.SwiftUI/documentation/SwiftUI/Bindable`` property wrapper instead; > for example, `@Bindable var model: DataModel`. For more information, see > . ## Topics ### Creating an observed object [`init(wrappedValue:)`](/documentation/SwiftUI/ObservedObject/init(wrappedValue:)) Creates an observed object with an initial wrapped value. [`init(initialValue:)`](/documentation/SwiftUI/ObservedObject/init(initialValue:)) Creates an observed object with an initial value. ### Getting the value [`wrappedValue`](/documentation/SwiftUI/ObservedObject/wrappedValue) The underlying value that the observed object references. [`projectedValue`](/documentation/SwiftUI/ObservedObject/projectedValue) A projection of the observed object that creates bindings to its properties. [`ObservedObject.Wrapper`](/documentation/SwiftUI/ObservedObject/Wrapper) A wrapper of the underlying observable object that can create bindings to its properties. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)