Binding value from an ObservableObject

Binding variables can be created in the following ways:

1. @State variable’s projected value provides a Binding<Value>
2. @ObservedObject variable’s projected value provides a wrapper from which you can get the Binding<Subject> for all of it’s properties
3. Point 2 applies to @EnvironmentObject as well.
4. You can create a Binding variable by passing closures for getter and setter as shown below:

let button = SaleButton(isOn: .init(get: { car.isReadyForSale },
                                    set: { car.isReadyForSale = $0} ))

Note:

• As @nayem has pointed out you need @State / @ObservedObject / @EnvironmentObject / @StateObject (added in SwiftUI 2.0) in the view for SwiftUI to detect changes automatically.
• Projected values can be accessed conveniently by using $ prefix.