Panning and Scrolling in Windows Store Apps

Introduction

In this article I describe how to create a Windows Store App for panning and scrolling large images using JavaScript. Panning and scrolling is used to allow an end-user to reach additional content that otherwise would not fit into a view. There are a few types of panning and scrolling to consider:

Horizontal: User can move content left/right.
Vertical: User can move content up/down both axes.
Unrailed: User is free to move the content in any direction.
Railed: User motion is locked to an axis, if close enough to the axis.

With the new ms-overflow-style property, you can control the type of scrollbar and when it appears.

I assume you can create a simple Windows Store App using JavaScript. For more help visit Simple Windows Store Apps using JavaScript.

To start the creation of the app, add two JavaScript pages by right-clicking on the js folder in the Solution Explorer and select Add > new item > JavaScript Page and then give an appropriate name. In the same way, add one HTML page to your project.

Write the following code in default.html:

<!DOCTYPE html>

<html>

<head>

</head>

</div>

</body>

</html>

Write the following code in default.js:

(function () {

"use strict";

var AppTitle = "";

var pages = [

{ url: "page.html" }

];

function activated(eventObject) {

if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) {

eventObject.setPromise(WinJS.UI.processAll().then(function () {

var url = WinJS.Application.sessionState.lastUrl || pages[0].url;

return WinJS.Navigation.navigate(url);

}));

}

WinJS.Navigation.addEventListener("navigated", function (eventObject) {

var url = eventObject.detail.location;

var host = document.getElementById("contentHost");

host.winControl && host.winControl.unload && host.winControl.unload();

WinJS.Utilities.empty(host);

eventObject.detail.setPromise(WinJS.UI.Pages.render(url, host, eventObject.detail.state).then(function () {

WinJS.Application.sessionState.lastUrl = url;

}));

});

WinJS.Namespace.define("app", {

AppTitle: AppTitle,

pages: pages

});

WinJS.Application.addEventListener("activated", activated, false);

WinJS.Application.start();

})();

Write the following code in page.html:

<!DOCTYPE html>

<html>

<head>

</head>

<body>

<label id="PanningTypeLabel">Select:</label>

<option value="Horizontal">Horizontal</option>

<option value="Vertical">Vertical</option>

<option value="Unrailed">Unrailed</option>

<option value="Railed">Railed</option>

</select>

<br />

<label id="ScrollbarStyleLabel">Set style:</label>

<option selected="selected" value="scrollbar">scrollbar</option>

<option selected="selected" value="-ms-autohiding-scrollbar">-ms-autohiding-scrollbar</option>

</select>

</div>

</div>

</body>

</html>

Write the following code in script.js:

(function () {

"use strict";

var page = WinJS.UI.Pages.define("page.html", {

processed: function (element, options) {

document.getElementById("PanningType").addEventListener("change", changePanningType, false);

document.getElementById("ScrollbarStyle").addEventListener("change", changeOverflowStyle, false);

}

});

function changePanningType(changedEvent) {

var myScrollElement = document.getElementById("page1_Scroller");

var panType = changedEvent.target.options.value;

myScrollElement.className = "ManipulationContainer " + panType;

}

function changeOverflowStyle(changedEvent) {

var myScrollElement = document.getElementById("page1_Scroller");

myScrollElement.style["-ms-overflow-style"] = changedEvent.target.options.value;

}

})();

Write the following code in script1.js:

(function () {

var pageOutput = WinJS.Class.define(

function (element, options) {

element.winControl = this;

this.element = element;

new WinJS.Utilities.QueryCollection(element)

.setAttribute("role", "region")

.setAttribute("aria-labelledby", "outputLabel")

.setAttribute("aria-live", "assertive");

element.id = "output";

this._addOutputLabel(element);

this._addStatusOutput(element);

}, {

_addOutputLabel: function (element) {

var label = document.createElement("h2");

label.id = "outputLabel";

label.textContent = "Output";

element.parentNode.insertBefore(label, element);

_addStatusOutput: function (element) {

var statusDiv = document.createElement("div");

statusDiv.id = "statusMessage";

element.insertBefore(statusDiv, element.childNodes[0]);

}

);

var currentpageUrl = null;

WinJS.Navigation.addEventListener("navigating", function (evt) {

currentpageUrl = evt.detail.location;

});

WinJS.log = function (message, tag, type) {

var statusDiv = document.getElementById("statusMessage");

};

function activated(e) {

WinJS.Utilities.query("#featureLabel")[0].textContent = app.AppTitle;

}

WinJS.Application.addEventListener("activated", activated, false);

WinJS.Namespace.define("app", {

pageOutput: pageOutput

});

})();

Output:

Summary

In this app I described panning and scrolling an image in a Windows Store app using JavaScript. I hope this article has helped you to understand this topic. Please share if you know more about this. Your feedback and constructive contributions are welcome.