---
title: "subscript(dynamicMember:)"
framework: swiftui
role: symbol
role_heading: Instance Subscript
path: "swiftui/binding/subscript(dynamicmember:)"
---

# subscript(dynamicMember:)

Returns a binding to the resulting value of a given key path.

## Declaration

```swift
subscript<Subject>(dynamicMember keyPath: WritableKeyPath<Value, Subject>) -> Binding<Subject> { get }
```

## Parameters

- `keyPath`: A key path to a specific resulting value.

## Return Value

Return Value A new binding.

## Overview

Overview Use dynamic member lookup to project a property of the binding’s wrapped value from a key path into a new binding. The returned value is read from, and written to, the original binding. This can be useful when a view accepts a binding for a type that only matches a property of a value from an existing binding. For example, the PlayerView controls the current position for an episode using a Slider, and whether the episode is a favorite using a Toggle. The view projects the currentPosition and isFavorite properties of Episode into bindings that each of these views accept using dynamic member lookup. struct Episode {     var title: LocalizedStringKey     var duration: TimeInterval     var currentPosition: TimeInterval     var isFavorite: Bool }

struct PlayerView: View {     @Binding var episode: Episode

var body: some View {         Text(episode.title)         Toggle("Favorite", isOn: $episode.isFavorite)         Slider(             value: $episode.currentPosition,             in: 0...episode.duration         )     } }

## See Also

### Getting the value

- [wrappedValue](swiftui/binding/wrappedvalue.md)
- [projectedValue](swiftui/binding/projectedvalue.md)