I just want to save some string into the local folder in a metro app, the code goes:
public GroupedItemsPage()
{
this.InitializeComponent();
Loaded += OnLoaded;
}
async private void OnLoaded(object sender, RoutedEventArgs routedEventArgs)
{
var storageFolder = ApplicationData.Current.LocalFolder;
var file = await storageFolder.CreateFileAsync("news.json", CreationCollisionOption.ReplaceExisting);
await FileIO.WriteTextAsync(file, "test");
}
But always got an FileNotFoundException exception, I'm creating a file instead of getting a file, so I don't know what's wrong with this code snippet.
Could anybody show me how to fix this problem? Thx in advance.
Related
I have a html string and it has local css,js paths. But Html is not working with these local paths. We searced but in every example, they have loaded html with writing inline. But I have to work disconnect and there is so much css,js assests. If i write inline, i am worried about it will load slow and i think it so senseless. Then i decided to change a local html file and load html from that file.
How can i load html from a local file?
This is my example code:
StorageFolder localFolder =
Windows.Storage.ApplicationData.Current.LocalFolder;
string desiredName = "mobile.html";
StorageFile newFile =
await localFolder.CreateFileAsync(desiredName,CreationCollisionOption.OpenIfExists);
using (var stream = await newFile.OpenStreamForWriteAsync())
{
stream.Write(fileBytes, 0, fileBytes.Length);
}
webViewFormResponse.Source = new Uri(newFile.Path);
newFile.Path like this: C:\Data\Users\DefApps\APPDATA\Local\Packages\9f4082ad-ad69-4cb8-8749-751ee4c5e46d_x2xndhe6jjw20\LocalState\mobile.html
You can use the NavigateToLocalStreamUri method of the WebView
e.g.
In WebView Loaded event
private void WebView_Loaded(object sender, RoutedEventArgs e)
{
Uri uri = MyWebView.BuildLocalStreamUri("LocalData", "mobile.html");
LocalUriResolver resolver = new LocalUriResolver();
MyWebView.NavigateToLocalStreamUri(uri, resolver);
}
And the Uri resolver class
public sealed class LocalUriResolver : IUriToStreamResolver
{
public IAsyncOperation<IInputStream> UriToStreamAsync(Uri uri)
{
if (uri == null)
{
throw new Exception();
}
string path = uri.AbsolutePath;
return GetContent(path).AsAsyncOperation();
}
private async Task<IInputStream> GetContent(string uriPath)
{
try
{
Uri localUri = new Uri("ms-appdata:///local" + uriPath);
StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(localUri);
IRandomAccessStream stream = await file.OpenReadAsync();
return stream.GetInputStreamAt(0);
}
catch (Exception)
{
throw new Exception("Invalid path");
}
}
}
I'm developing app for Windows Phone 8, and i'm trying to share image via ShareMediaTask.
The procedure? that i use for it is as follows :
private static Microsoft.Phone.Tasks.ShareMediaTask shareMediaTask;
public static void shareCurrentCroppedImage ()
{
shareMediaTask = new Microsoft.Phone.Tasks.ShareMediaTask();
GC.Collect();
Debug.WriteLine("file path : {0}", currentFileName);
shareMediaTask.FilePath = currentFileName;
shareMediaTask.Show();
}
The path from console looks like this:
file path : C:\Data\Users\Public\Pictures\Saved Pictures\Lo_1.jpg
Unfortunately, when i call this proc ( from button click event ) the app shuts down, a black screen shows, but then suddenly workflow returns back to my app without any sharing UI. How can i fix this issue? Any help would be appreciated!
This is the code which worked for me..
I had created a PhotoChooserTask to capture an image or open an existing image from library and then when this PhotoChooserTask completes, I create a ShareMediaTask and set its Filepath property to The "OriginalFileName" filed from the parameter photoresult e.
The issue with your code, i think, might be this path of image.
private void OnShareMediaTaskClicked(object sender, RoutedEventArgs e)
{
var photoChooserTask = new PhotoChooserTask { ShowCamera = true };
photoChooserTask.Completed += OnPhotoChooserTaskCompleted;
photoChooserTask.Show();
}
void OnPhotoChooserTaskCompleted(object sender, PhotoResult e)
{
var photoChooserTask = (PhotoChooserTask)sender;
photoChooserTask.Completed -= OnPhotoChooserTaskCompleted;
var shareMediaTask = new ShareMediaTask ();
shareMediaTask.FilePath = e.OriginalFileName;
shareMediaTask.Show();
}
I have set the OnShareMEdiaClicked as ahandler of an onClick event for a button. and the rest flow is clear.
Hope this helps.
I'm working on a Windows Phone 8 app.
I'm having issue appending to my JSON file.
It works fine if I keep the app open but once I close it and come back in it starts back writing from the beginning of the file.
Relevant code:
private async void btnSave_Click(object sender, RoutedEventArgs e)
{
// Create a entry and intialize some values from textbox...
GasInfoEntries _entry = null;
_entry = new GasInfoEntries();
_entry.Gallons = TxtBoxGas.Text;
_entry.Price = TxtBoxPrice.Text;
_GasList.Add(_entry);
//TxtBlockPricePerGallon.Text = (double.Parse(TxtBoxGas.Text) / double.Parse(TxtBoxPrice.Text)).ToString();
// Serialize our Product class into a string
string jsonContents = JsonConvert.SerializeObject(_GasList);
// Get the app data folder and create or open the file we are storing the JSON in.
StorageFolder localFolder = ApplicationData.Current.LocalFolder;
StorageFile textfile = await localFolder.CreateFileAsync("gasinfo.json", CreationCollisionOption.OpenIfExists); //if get await operator error add async to class (btnsave)
//open file
using (IRandomAccessStream textstream = await textfile.OpenAsync(FileAccessMode.ReadWrite))
{
//write JSON string
using (DataWriter textwriter = new DataWriter(textstream))
//using (DataWriter textwriter = new DataWriter(textstream))
{
textwriter.WriteString(jsonContents);
await textwriter.StoreAsync(); //writes buffer to store
}
}
}
private async void btnShow_Click(object sender, RoutedEventArgs e)
{
StorageFolder localfolder = ApplicationData.Current.LocalFolder;
try
{
// Getting JSON from file if it exists, or file not found exception if it does not
StorageFile textfile = await localfolder.GetFileAsync("gasinfo.json");
using (IRandomAccessStream textstream = await textfile.OpenReadAsync())
{
//read text stream
using (DataReader textreader = new DataReader(textstream))
{
//get size ...not sure what for think check the file size (lenght) then based on next 2 commands waits until its all read
uint textlength = (uint)textstream.Size;
await textreader.LoadAsync(textlength);
//read it
string jsonContents = textreader.ReadString(textlength);
// deserialize back to gas info
_GasList = JsonConvert.DeserializeObject<List<GasInfoEntries>>(jsonContents) as List<GasInfoEntries>;
displayGasInfoEntries();
}
}
}
catch
{
txtShow.Text = "something went wrong";
}
}
private void displayGasInfoEntries()
{
txtShow.Text = "";
StringBuilder GasString = new StringBuilder();
foreach (GasInfoEntries _entry in _GasList)
{
GasString.AppendFormat("Gallons: {0} \r\n Price: ${1} \r\n", _entry.Gallons, _entry.Price); // i think /r/n means Return and New line...{0} and {1} calls "variables" in json file
}
txtShow.Text = GasString.ToString();
}
Thanks
Do you call the btnShow_Click each time you've started the app? Because otherwise the _GasList will be empty; if you now call the btnSave_Click all previous made changes will be lost.
So please make sure, that you restore the previously saved json data before you add items to the _GasList.
I would like to download a xml file from web, then save it to the local storage but I do not know how to do that. Please to help me clearly or give me an example. Thank you.
Downloading a file is a huge subject and can be done in many ways. I assume that you know the Uri of the file you want to download, and want you mean by local is IsolatedStorage.
I'll show three examples how it can be done (there are also other ways).
1. The simpliest example will dowload string via WebClient:
public static void DownloadFileVerySimle(Uri fileAdress, string fileName)
{
WebClient client = new WebClient();
client.DownloadStringCompleted += (s, ev) =>
{
using (IsolatedStorageFile ISF = IsolatedStorageFile.GetUserStoreForApplication())
using (StreamWriter writeToFile = new StreamWriter(ISF.CreateFile(fileName)))
writeToFile.Write(ev.Result);
};
client.DownloadStringAsync(fileAdress);
}
As you can see I'm directly downloading string (ev.Result is a string - that is a disadventage of this method) to IsolatedStorage.
And usage - for example after Button click:
private void Download_Click(object sender, RoutedEventArgs e)
{
DownloadFileVerySimle(new Uri(#"http://filedress/myfile.txt", UriKind.Absolute), "myfile.txt");
}
2. In the second method (simple but more complicated) I'll use again WebClient and I'll need to do it asynchronously (if you are new to this I would suggest to read MSDN, async-await on Stephen Cleary blog and maybe some tutorials).
First I need Task which will download a Stream from web:
public static Task<Stream> DownloadStream(Uri url)
{
TaskCompletionSource<Stream> tcs = new TaskCompletionSource<Stream>();
WebClient wbc = new WebClient();
wbc.OpenReadCompleted += (s, e) =>
{
if (e.Error != null) tcs.TrySetException(e.Error);
else if (e.Cancelled) tcs.TrySetCanceled();
else tcs.TrySetResult(e.Result);
};
wbc.OpenReadAsync(url);
return tcs.Task;
}
Then I'll write my method downloading a file - it also need to be async as I'll use await DownloadStream:
public enum DownloadStatus { Ok, Error };
public static async Task<DownloadStatus> DownloadFileSimle(Uri fileAdress, string fileName)
{
try
{
using (Stream resopnse = await DownloadStream(new Uri(#"http://filedress/myfile.txt", UriKind.Absolute)))
using (IsolatedStorageFile ISF = IsolatedStorageFile.GetUserStoreForApplication())
{
if (ISF.FileExists(fileName)) return DownloadStatus.Error;
using (IsolatedStorageFileStream file = ISF.CreateFile(fileName))
resopnse.CopyTo(file, 1024);
return DownloadStatus.Ok;
}
}
catch { return DownloadStatus.Error; }
}
And usage of my method for example after Button click:
private async void Downlaod_Click(object sender, RoutedEventArgs e)
{
DownloadStatus fileDownloaded = await DownloadFileSimle(new Uri(#"http://filedress/myfile.txt", UriKind.Absolute), "myfile.txt");
switch (fileDownloaded)
{
case DownloadStatus.Ok:
MessageBox.Show("File downloaded!");
break;
case DownloadStatus.Error:
default:
MessageBox.Show("There was an error while downloading.");
break;
}
}
This method can have problems for example if you try to download very big file (example 150 Mb).
3. The third method - uses WebRequest with again async-await, but this method can be changed to download files via buffer, and therefore not to use too much memory:
First I'll need to extend my Webrequest by a method that will asynchronously return a Stream:
public static class Extensions
{
public static Task<Stream> GetRequestStreamAsync(this WebRequest webRequest)
{
TaskCompletionSource<Stream> taskComplete = new TaskCompletionSource<Stream>();
webRequest.BeginGetRequestStream(arg =>
{
try
{
Stream requestStream = webRequest.EndGetRequestStream(arg);
taskComplete.TrySetResult(requestStream);
}
catch (Exception ex) { taskComplete.SetException(ex); }
}, webRequest);
return taskComplete.Task;
}
}
Then I can get to work and write my Downloading method:
public static async Task<DownloadStatus> DownloadFile(Uri fileAdress, string fileName)
{
try
{
WebRequest request = WebRequest.Create(fileAdress);
if (request != null)
{
using (Stream resopnse = await request.GetRequestStreamAsync())
{
using (IsolatedStorageFile ISF = IsolatedStorageFile.GetUserStoreForApplication())
{
if (ISF.FileExists(fileName)) return DownloadStatus.Error;
using (IsolatedStorageFileStream file = ISF.CreateFile(fileName))
{
const int BUFFER_SIZE = 10 * 1024;
byte[] buf = new byte[BUFFER_SIZE];
int bytesread = 0;
while ((bytesread = await resopnse.ReadAsync(buf, 0, BUFFER_SIZE)) > 0)
file.Write(buf, 0, bytesread);
}
}
return DownloadStatus.Ok;
}
}
return DownloadStatus.Error;
}
catch { return DownloadStatus.Error; }
}
Again usage:
private async void Downlaod_Click(object sender, RoutedEventArgs e)
{
DownloadStatus fileDownloaded = await DownloadFile(new Uri(#"http://filedress/myfile.txt", UriKind.Absolute), "myfile.txt");
switch (fileDownloaded)
{
case DownloadStatus.Ok:
MessageBox.Show("File downloaded!");
break;
case DownloadStatus.Error:
default:
MessageBox.Show("There was an error while downloading.");
break;
}
}
Those methods of course can be improved but I think this can give you an overview how it can look like. The main disadvantage of these methods may be that they work in foreground, which means that when you exit your App or hit start button, downloading stops. If you need to download in background you can use Background File Transfers - but that is other story.
As you can see you can reach your goal in many ways. You can read more about those methods on many pages, tutorials and blogs, compare an choose the most suitable.
Hope this helps. Happy coding and good luck.
xmlns:VideoStream="using:Microsoft.PlayerFramework"
VideoStream:MediaPlayer Source="http://155.41.145.37/mjpg/video.mjpg"
Worked fine when i change the Source pointed to .mp4 file. When changing to .mjpg it won't work. When running it shows the error " This video is failed to play".
Please help
Vishnu Aravind
This works:
Doc: https://channel9.msdn.com/coding4fun/articles/MJPEG-Decoder
Download:
http://mjpeg.codeplex.com/
Sample code:
MjpegDecoder _mjpeg;
public MainPage()
{
this.InitializeComponent();
_mjpeg = new MjpegDecoder();
_mjpeg.FrameReady += mjpeg_FrameReady;
_mjpeg.ParseStream(new Uri("http://155.41.145.37/mjpg/video.mjpg"));
}
private async void mjpeg_FrameReady(object sender, FrameReadyEventArgs e)
{
// Convert IBuffer to IRandomAccessStream.
var ras = new InMemoryRandomAccessStream();
await ras.WriteAsync(e.FrameBuffer);
ras.Seek(0);
// Show image.
var bitmap = new BitmapImage();
await bitmap.SetSourceAsync(ras);
image.Source = bitmap;
}