---
title: "callAsFunction(value:)"
framework: swiftui
role: symbol
role_heading: Instance Method
path: "swiftui/openwindowaction/callasfunction(value:)"
---

# callAsFunction(value:)

Opens a window defined by a window group that presents the type of the specified value.

## Declaration

```swift
@MainActor @preconcurrency func callAsFunction<D>(value: D) where D : Decodable, D : Encodable, D : Hashable
```

## Parameters

- `value`: The value to present.

## Discussion

Discussion Don’t call this method directly. SwiftUI calls it when you call the openWindow action with a value: openWindow(value: message.id) For information about how Swift uses the callAsFunction() method to simplify call site syntax, see Methods with Special Names in The Swift Programming Language.

## See Also

### Calling the action

- [callAsFunction(id:)](swiftui/openwindowaction/callasfunction(id:).md)
- [callAsFunction(id:value:)](swiftui/openwindowaction/callasfunction(id:value:).md)