Develop Reference

UWP, Access to the path is denied

I read some topic about file permission.
Someone said "App can access directories and files which the user manually selected with the FileOpenPicker or FolderPicker"
My codes are like as below:
public async void CsvParse()
{
var picker = new Windows.Storage.Pickers.FileOpenPicker();
picker.FileTypeFilter.Add(".csv");
Windows.Storage.StorageFile file = await picker.PickSingleFileAsync();
if (file != null)
{
string[] lines = File.ReadAllLines(file.Path);//this is where app stops working and gives error message.
}
}
Even when I choose file with FilePicker, it still gives me error. But when I choose file from appx folder, it works fine.
Is there a way to access other locations than app's folder?

try it this way:
public async void CsvParse()
{
var picker = new Windows.Storage.Pickers.FileOpenPicker();
picker.FileTypeFilter.Add(".csv");
Windows.Storage.StorageFile file = await picker.PickSingleFileAsync();
if (file != null)
{
IList<string> lines = await FileIO.ReadLinesAsync(file);//this is where app stops working and gives error message.
}
}
the StorageFile is the way you get access to a file. File.ReadAllLines(file.Path) you are passing a Filename, not the StorageFile but just the filepath is not enough for getting access

how to launch files from sd card in uwp?

I'm trying to create a file explorer for windows 10 mobile
I need to launch files with default app from pathes (not installed directory)
ex. "d:\test.pdf"
Here's what I've tried:
string p = #"a.jpg";
StorageFolder externalDevices = Windows.Storage.KnownFolders.RemovableDevices;
StorageFile file = await externalDevices.GetFileAsync(p);
var success = await Launcher.LaunchFileAsync(fff);

you can use Windows.System.Launcher API to launch the default handler for a file you can read more here
async void DefaultLaunch()
{
// Path to the file in the app package to launch
string imageFile = #"images\test.png";
var file = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFileAsync(imageFile);
if (file != null)
{
// Launch the retrieved file
var success = await Windows.System.Launcher.LaunchFileAsync(file);
if (success)
{
// File launched
}
else
{
// File launch failed
}
}
else
{
// Could not find file
}
}

If you want to access files from SD card, please make sure that you have read the What you can and can't access on the SD card section on document.
Your app can only read and write files of file types that the app has registered to handle in the app manifest file.
Your app can also create and manage folders.
Make sure that you check "Removable Storage" in the capabilities of the appxmanifest.
You must declare a file type association in the Package.appxmanifest in order to read files from the SD card. The following is an example of one that I set up:
Then, I used the following code sample to launch a picture which is contained in "New folder" on SD card successfully.
string p = #"1.jpg";
StorageFolder externalDevices = Windows.Storage.KnownFolders.RemovableDevices;
var rootfolder = (await externalDevices.GetFoldersAsync()).FirstOrDefault();
var folder = await rootfolder.GetFolderAsync("New folder");
var file = await folder.GetFileAsync(p);
var success = await Launcher.LaunchFileAsync(file);

No permission to delete / overwrite files in subfolders of ApplicationData.Current.LocalFolder

I am facing an problem with files that I create within my application in dedicated sub folders of ApplicationData.Current.LocalFolder. I can create sub folders with ApplicationData.Current.LocalFolder.CreateFolderAsync() and even place files in it. But as soon as I try to overwrite or delete files, I get an access violation exception. (Read Access is still possible)
Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))
I looked up the UWP pages but most of the time they simply create a new folder and that's it.
My attempt to overwrite the file:
public async Task WriteFileAsync(string filename, Stream fileContent)
{
StorageFolder folder = ApplicationData.Current.LocalFolder;
var deepFolders = filename.Split('/');
if (deepFolders != null)
{
for (var i=0; i<deepFolders.Length - 1; i++)
{
folder = await folder.GetFolderAsync(deepFolders[i]);
}
filename = deepFolders[deepFolders.Length - 1];
}
try
{
StorageFile oldFile = await folder.GetFileAsync(filename);
await oldFile.DeleteAsync();
}
catch (FileNotFoundException) { }
StorageFile file = await folder.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);
}
The first time it runs just fine, but as soon as the overwrite should take place, I get the exception.
Running the whole stuff without sub-folders works like charm.
The attempt to first read and delete the file resulted in the same exception already during the deletion.

How to add folder to StorageLibrary without RequestAddFolderAsync in C#

I need to save app files to plugged SD card. I'm using UWP and Windows 10.
MSDN tells how to do it with Windows Libraries.
var myPicsLibrary = await Windows.Storage.StorageLibrary.GetLibraryAsync(Windows.Storage.KnownLibraryId.Pictures);
await myPicsLibrary.RequestAddFolderAsync();
RequestAddFolderAsync() shows file picker, where user can choose folder to add into Pictures. In my case it's a folder, created on SD card.
Is there a way to do this thing without file picker dialog?
I'm trying to do like this:
var myPicsLibrary = await Windows.Storage.StorageLibrary.GetLibraryAsync(Windows.Storage.KnownLibraryId.Pictures);
// Get the logical root folder for all external storage devices.
StorageFolder externalDevices = Windows.Storage.KnownFolders.RemovableDevices;
// Get the first child folder, which represents the SD card.
StorageFolder sdCard = (await externalDevices.GetFoldersAsync()).FirstOrDefault();
var folder = await sdCard.CreateFolderAsync("MySDCardFolder");
myPicsLibrary.Folders.Insert(myDocs.Folders.Count+1, folder); // NotImplementedException: 'The method or operation is not implemented.'
myPicsLibrary.Folders.Add(folder); // NotImplementedException: 'The method or operation is not implemented.'
Or maybe I can do the same without using Windows Libraries directly working with SDCard?
Thanks a lot!
EDIT:
In the another hand my question sounds like "How to save files to plugged SD card?"

The StorageLibrary.Folders gets the folders in the current library, it return the IObservableVector of the StorageFolder. When we add the folder into the IObservableVector, it will not change the folder in files system. It will throw the "The method or operation is not implemented." exception.
We should be able to get the name of the folder, and create the folder uses that name. Then we can StorageFile.CopyAsync method to copy the file that in your folder.
For example:
public static async Task CopyFolderAsync(StorageFolder source, StorageFolder destinationContainer, string desiredName = null)
{
StorageFolder destinationFolder = null;
destinationFolder = await destinationContainer.CreateFolderAsync(
desiredName ?? source.Name, CreationCollisionOption.ReplaceExisting);
foreach (var file in await source.GetFilesAsync())
{
await file.CopyAsync(destinationFolder, file.Name, NameCollisionOption.ReplaceExisting);
}
foreach (var folder in await source.GetFoldersAsync())
{
await CopyFolderAsync(folder, destinationFolder);
}
}
Then we can use the CopyFolderAsync method to copy the folder in the Picture Library.
var myPicsLibrary = await Windows.Storage.StorageLibrary.GetLibraryAsync(Windows.Storage.KnownLibraryId.Pictures);
var myfolder = myPicsLibrary.Folders[0];
StorageFolder externalDevices = Windows.Storage.KnownFolders.RemovableDevices;
StorageFolder sdCard = (await externalDevices.GetFoldersAsync()).FirstOrDefault();
var folder = await sdCard.CreateFolderAsync("MySDCardFolder");
await CopyFolderAsync(folder, myfolder);

As I get from your question you need to create a Folder in PicturesLibrary .
You can use the code below to add a folder into PicturesLibrary
await Windows.Storage.KnownFolders.PicturesLibrary.CreateFolderAsync("MySDCardFolder");
if you want to make it on SD Card only Maybe KnownFolders.RemovableDevices Should be helpful . I didn't used KnownFolders.RemovableDevices yet but if you have any issue let me know to test it on my phone directly

Search files in project folder dynamically

In my Windows Store project I have some .jpg files in my Assets folder. How can I dynamically get all the .jpg files from that folder?
I've tried:
StorageFolder folder = await StorageFolder.GetFolderFromPathAsync("ms-appx:///Assets/");
var fileList = await folder.GetFilesAsync(CommonFileQuery.DefaultQuery);
Must work somehow like this (with a different CommonFileQuery) but this is not working for me. (System Exception at line 1 - wrong path name).
Second question: how do I test if my Assets folder contains "movie.mp4"?
Thank you!

You can use Directory.EnumerateFiles(sourceDirectory, "*.jpg", SearchOption.AllDirectories);
Question 2:
You can use File.Exists(filePath);
Edit
As per your comment, I found this which uses GetFileFromApplicationUriAsync instead of GetFolderFromPathAsync
or
StorageFolder installedLocation = Windows.ApplicationModel.Package.Current.InstalledLocation;
var files = installedLocation.GetFolderFromPathAsync("Assets");
Q2 seems like you can use
TryGetItemAsync

This is the complete solution for my scenario:
Get Files within a project folder of a certain file type.
Check if a file exists within a project folder.
1:
StorageFolder installedLocation = Windows.ApplicationModel.Package.Current.InstalledLocation;
StorageFolder subFolder = await installedLocation.GetFolderAsync("Assets");
subFolder = await subFolder.GetFolderAsync("Images");
List<String> fileType = new List<String>();
fileType.Add(".jpg");
var queryOptions = new QueryOptions(CommonFileQuery.DefaultQuery, fileType);
var query = subFolder.CreateFileQueryWithOptions(queryOptions);
var fileList = await query.GetFilesAsync();
2:
try
{
var video = await subFolder.GetFileAsync("Video.mp4");
}
catch (FileNotFoundException)
{
Debug.WriteLine("No Video found");
}