---
title: "show(selectionHandler:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nscolorsampler/show(selectionhandler:)"
---

# show(selectionHandler:)

Displays the system color-sampling interface asynchronously and reports the selected color back to your app.

## Declaration

```swift
func show(selectionHandler: @escaping @Sendable (NSColor?) -> Void)
```

```swift
func sample() async -> NSColor?
```

## Parameters

- `selectionHandler`: The handler block for processing the user-selected color. AppKit calls this block on your app’s main thread. This block has no return value and takes the following parameter:

## Discussion

Discussion This method displays the color-sampling interface and returns immediately. The color-sampling interface magnifies the onscreen pixels and makes it easier for the user to select a single pixel. When the user clicks any mouse button, AppKit dismisses the interface and calls selectionHandler with the results.