MediaQueryList.md

MediaQueryList

Namespace: SpawnDev.SpawnJS.JSObjects
Inherits: EventTarget
Source: JSObjects/MediaQueryList.cs
MDN Reference: MediaQueryList on MDN

A MediaQueryList object stores information on a media query applied to a document, with support for both immediate and event-driven matching against the state of the document. https://developer.mozilla.org/en-US/docs/Web/API/MediaQueryList

Constructors

Signature	Description
MediaQueryList(SpawnJSObjectReference _ref)	Deserialization constructor

Properties

Property	Type	Access	Description
Matches	bool	get	A boolean value that returns true if the document currently matches the media query list, or false if not.
Media	string	get	A string representing a serialized media query.

Events

Event	Type	Description
OnChange	ActionEvent<MediaQueryListEvent>	Sent to the MediaQueryList when the result of running the media query against the document changes. For example, if the media query is (min-width: 400px), the change event is fired any time the width of the document's viewport changes such that its width moves across the 400px boundary in either direction.

Examples

SpawnDev.SpawnJS Mapping Note: The JavaScript examples below show the standard Web API usage. In SpawnDev.SpawnJS, the same API is available with C# conventions:

• Properties and methods use PascalCase (e.g., readyState becomes ReadyState)
• Events use ActionEvent with +=/-= (e.g., addEventListener("click", fn) becomes OnClick += handler)
• Async methods return Task<T> instead of Promise<T>
• Objects should be disposed with using statements
• Access via JS.Get<MediaQueryList>(...) or constructor new MediaQueryList(...)

const para = document.querySelector("p");
const mql = window.matchMedia("(width <= 600px)");

function screenTest(e) {
  if (e.matches) {
    /* the viewport is 600 pixels wide or less */
    para.textContent = "This is a narrow screen — less than 600px wide.";
    document.body.style.backgroundColor = "red";
  } else {
    /* the viewport is more than 600 pixels wide */
    para.textContent = "This is a wide screen — more than 600px wide.";
    document.body.style.backgroundColor = "blue";
  }
}

mql.addEventListener("change", screenTest);

See full example on MDN