I ran across this today and wanted to share the fix. I have seen it crop up both XAML/C# and HTML/JS projects and has to do more with how the app is registered.
The error appears when you attempt to debug your Windows 8 metro Style App you will be prompted with a dialog informing you the application could not be started.
Clicking on Yes for more information will show you the id of the Metro Style App and point you to the Debug->Windows->Output window. Unfortunately looking in the Output window doesn’t give you much information either.
The goods news is the fix is simple! Simply exit out of Visual Studio 11 Beta and navigate to the solution file of your project. Once there delete everything inside of the bin folder.
Then open the project back up in Visual Studio 11 Beta and it should deploy correctly for debugging!
-Dave
You may also want to check out my previous Windows 8 Metro Style Development Tips:
In my last blog post I discussed the importance of supporting the numerous shapes and sizes Windows 8 devices will be in our Metro Style Apps. This post will cover how to handle viewstate changes in our game which happens when the user runs our app side by side with another Metro Style App.
The Guidelines for snapped and fill views define three states we will need to handle. The first, full screen, is the default state for all Metro Style Apps. When a user drags another window onto the screen they have the option of having it become the current running app, snapping the new app to the side, or running it filled. In the case of a full screen app only one application would be visible so if the user dragged another app onto the screen our application would go into suspend mode after 10 seconds of inactivity (more on app lifecycle in another post). If they snapped the app our game would go into filled mode. If they snapped our game then the app they dragged over would move into snapped mode.
Here are what the three different states look like:
In the below example my game is running full screen as a normal Metro Style App.
In the snap example I dragged over Internet Explorer onto the screen and was given a slider bar in between both apps. By moving the slider over to the left I was able to have the game run in a small window and our browser in a larger window. In this scenario our game will report a snapped Viewstate and Internet Explorer will report Filled.
If I wanted more screen space for my game I could drag the slider bar over to the right. This would then send our game into a Filled state and our Internet Explorer window into a Snapped state.
It is important to point out I can also rearrange these windows by grabbing the snapped Internet Explorer window and moving it to the left. This will automatically move our game filled window to the right. Grabbing either window and moving it off of the bottom of the screen will return the remaining app to full screen mode.
The first thing we need to do is define how wide these new screen states will be. The good news is that Snapped view will always be 320px in width which will make adjusting our game coordinate system much easier. Filled state will always be the width of the screen minus 320px and snapped state will always be 320px wide. Let’s go ahead and add a variable to handle the size of snapped view in our calculations.
var SNAPPED_VIEW = 320;
Next we need to set up the event handler for any Viewstate changes. This is done via the ApplicationView class for the current view. In the below example I am assigning the viewstatechanged event of the current application view to my own onViewStateChanged function.
//Handle View Layout Changes
Windows.UI.ViewManagement.ApplicationView.getForCurrentView().addEventListener("viewstatechanged", onViewStateChanged);
When onViewStateChanged runs it enumerates through all available viewstates and passes the current view state to a custom function I call showMenu.
function onViewStateChanged(eventArgs) {
var viewStates = Windows.UI.ViewManagement.ApplicationViewState, msg;
var newViewState = eventArgs.viewState;
if (newViewState === viewStates.snapped) {
showMenu('snapped');
} else if (newViewState === viewStates.filled) {
showMenu('filled');
} else if (newViewState === viewStates.fullScreenLandscape) {
showMenu('landscape');
} else if (newViewState === viewStates.fullScreenPortrait) {
//Currently not supported
}
showMenu is the same function I call when my game is first loaded or the user clicks on the AppBar to return to the menu. This will pause the game for our user when they are dragging in another app to work with. They can then continue game play when they are ready. The full updated showMenu function is as follows:
//Set Up Menu Screen UI Elements
function showMenu(event) {
menuEnabled = true;
txtPlayerName.style.visibility = "hidden";
txtScore.style.visibility = "hidden";
imgPlayer.style.visibility = "hidden";
imgMenu.style.visibility = "visible";
btnStart.style.visibility = "visible";
txtVersion.innerHTML = GAME_VERSION;
txtVersion.style.visibility = "visible";
txtLevel.style.visibility = "hidden";
//Detect View State
if (event === 'snapped') {
canvas.width = SNAPPED_VIEW;
else if (event === 'filled') {
canvas.width = FULLSCREEN_WIDTH - SNAPPED_VIEW;
else {
canvas.width = FULLSCREEN_WIDTH;
//Readjust canvas for Snapped/Filled modes
canvas.height = window.innerHeight;
SCREEN_HEIGHT = canvas.height;
SCREEN_WIDTH = canvas.width;
//Set boundries to be one ship size
MAX_X = canvas.width - (SHIP_WIDTH + 20);
MAX_Y = canvas.height - (SHIP_HEIGHT + 50);
var menuX, btnX, btnY;
menuX = (SCREEN_WIDTH - imgMenu.width) / 2;
btnX = (SCREEN_WIDTH - btnStart.clientWidth) / 2;
btnY = (SCREEN_HEIGHT - btnStart.clientHeight) / 2;
imgMenu.style.posLeft = menuX;
btnStart.style.posLeft = btnX;
btnStart.style.posTop = btnY;
//clear screen
ctx.clearRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
musicGame.pause();
musicMenu.play();
Specifically this function changes the width of our game screen and then re-calculates the size of the screen so that our ships will disappear when they hit the edge. This is done by grabbing the width of the current screen and then calculating in SNAPPED_VIEW.
Now that we are properly handling viewstate changes and adjusted our coordinate system correctly we need to update our game user interface. All Metro Style Apps will have predefined layouts for their viewstates thanks to CSS3 Media Queries. If you haven’t worked with CSS3 Media Queries much before I highly recommend Responsive Web Design by Ethan Marcotte. He takes you through designing a website application that adapts its screen layout based on different screen sizes and device form factors.
The default Metro Style App templates automatically do this for us by seting up media queries inside the default.css file. This is where you can adjust layout for all viewstates as well as portrait and landscape.
@media screen and (-ms-view-state: fullscreen-landscape) {
@media screen and (-ms-view-state: filled) {
@media screen and (-ms-view-state: snapped) {
#imgMenu {
-ms-transform: translate(0px, 0px) rotate(0deg) scale(0.50);
#btnStart {
-ms-transform: translate(0px, 0px) rotate(0deg) scale(0.60);
#txtNewLevel {
-ms-transform: translate(0px, 0px) rotate(0deg) scale(0.30);
#imgPlayer {
opacity: 0;
#txtLevel {
-ms-transform: translate(-120px, 0px) rotate(0deg) scale(0.30);
#txtPlayerName {
-ms-transform: translate(70px, 0px) rotate(0deg) scale(0.30);
#txtScore {
@media screen and (-ms-view-state: fullscreen-portrait) {
Due to Filled viewstate only shrinking by 320px I found all of my on screen elements to look fine as is.
Snapped mode presented some challenges as I needed to shrink both the gamescore, player name, and level texts. A lot of what you will do here is through trial and error. I kept tweaking the scale until it “felt right.” I chose to use CSS3 2D Transforms to scale out the text so that it filled the screen correctly at the same time remaining readable. I chose to drop the player image when in this mode as it became too small to be of any value. Here is a screenshot of the new snapped user interface layout while the game is being played.
You will notice I kept the sizes of the ships the same. I am currently debating whether I should scale them down or change the direction of the ships to vertical. This would almost give a different game experience when in snapped mode. That is the beauty of CSS3 Media Queries in action as we can completely change what elements look like based on the screen size.
I hope this post has given you an idea of how easy it is to handle Viewstate changes in your Metro Style App using CSS3 and JavaScript. If you are currently working on a Windows 8 app and want to get into the Windows Store I would love to hear about it!
Missed some of the local Windows 8 Camps? More are on the way!
Via my teammate Chris Bowen…
I previously mentioned the series of Windows Developer Camps - free, full-day events to help you learn about building Metro-style apps for Windows 8. They feature a mix of developer sessions plus a series of hands-on labs to help reinforce what you’ve learned. Well, it turns out they’re popular. So popular, in fact, that all of the Camps I listed earlier are full. However, more are on the way! Coming soon to these cities: Date Location Link May 22 Irving, TX Register May 23 Bellevue, WA Register May 24 Waltham, MA Register May 24 Chevy Chase, MD Register May 29 Minneapolis, MN Register June 1 New York, NY Register June 5 Downers Grove, IL Register Register soon, bring a PC with the Windows 8 Consumer Preview and Visual Studio 11 Beta installed, and enjoy Camp!
I previously mentioned the series of Windows Developer Camps - free, full-day events to help you learn about building Metro-style apps for Windows 8. They feature a mix of developer sessions plus a series of hands-on labs to help reinforce what you’ve learned.
Well, it turns out they’re popular. So popular, in fact, that all of the Camps I listed earlier are full.
However, more are on the way! Coming soon to these cities:
Register soon, bring a PC with the Windows 8 Consumer Preview and Visual Studio 11 Beta installed, and enjoy Camp!
If you would prefer to go at your own paced in a self study environment all of the Windows 8 Camp content is now available for download. There are also virtual Windows 8 Camps happening via the upcoming MSDN Webcast Windows 8 Development series. Once you are settled into coding your next masterpiece let me know about it so I can help you get a Windows Store token.
Great news! The Windows 8 Camp in a Box is now available for download. It includes all of the presentations, code samples, and hands on labs I showed off during the Windows 8 Camps and NYC Windows 8 Developer Event. The content is available in both XAML/C# and HTML/JavaScript versions.
If you have been looking for an opportunity to develop an application step by step this it! Full source code and instructions are provided in both html and docx formats. So print them out, pull up a chair, and code up the Contoso Cookbook sample at your own pace.
The Windows 8 Camps are still ongoing (across the globe!) too so if you haven’t attended one yet be sure to sign up or register for the upcoming MSDN Webcast Windows 8 Development series. Once you are settled into coding your next masterpiece let me know about it so I can help you get a Windows Store token.