I am currently working on a Windows 10 UWP App.
The App needs to Check if a certain PDF File exists called "01-introduction", and if so open it.
I already have the code for if the file does not exist.
The Code Below is what i currently have:
try
{
var test = await DownloadsFolder.CreateFileAsync("01-Introduction.pdf", CreationCollisionOption.FailIfExists);
}
catch
{
}
This code Does not work correctly because to check if the file exists here, I attempt to create the file. However if the file does not already exist an empty file will be created. I do not want to create anything if the file does not exist, just open the PDF if it does.
If possible, i would like to look inside a folder which is in the downloads folder called "My Manuals".
Any help would be greatly appreciated.
public async Task<bool> IsFilePresent(string fileName)
{
var item = await ApplicationData.Current.LocalFolder.TryGetItemAsync(fileName);
return item != null;
}
But not support Win8/WP8.1
https://blogs.msdn.microsoft.com/shashankyerramilli/2014/02/17/check-if-a-file-exists-in-windows-phone-8-and-winrt-without-exception/
There are two methods
1) You can use StorageFolder.GetFileAsync() as this is also supported by Windows 8.1 and WP 8.1 devices.
try
{
StorageFile file = await DownloadsFolder.GetFileAsync("01-Introduction.pdf");
}
catch
{
Debug.WriteLine("File does not exits");
}
2) Or you can use FileInfo.Exists only supported for windows 10 UWP.
FileInfo fInfo = new FileInfo("01-Introduction.pdf");
if (!fInfo.Exists)
{
Debug.WriteLine("File does not exits");
}
System.IO.File.Exists is UWP way too. I test now in Windows IOT. it just works.
This helped me in my case:
ApplicationData.Current.LocalFolder.GetFileAsync(path).AsTask().ContinueWith(item => {
if (item.IsFaulted)
return; // file not found
else { /* process file here */ }
});
This worked for me running my UWP C# app on Windows 10...
StorageFolder app_StorageFolder = await StorageFolder.GetFolderFromPathAsync( #App.STORAGE_FOLDER_PATH );
var item = await app_StorageFolder.TryGetItemAsync(relative_file_pathname);
return item != null;
public override bool Exists(string filePath)
{
try
{
string path = Path.GetDirectoryName(filePath);
var fileName = Path.GetFileName(filePath);
StorageFolder accessFolder = StorageFolder.GetFolderFromPathAsync(path).AsTask().GetAwaiter().GetResult();
StorageFile file = accessFolder.GetFileAsync(fileName).AsTask().GetAwaiter().GetResult();
return file != null;
}
catch
{
return false;
}
}
You can use System.IO.File.
Example:
// If file located in local folder. You can do the same for other locations.
string rootPath = ApplicationData.Current.LocalFolder.Path;
string filePath = Path.Combine(rootPath, "fileName.pdf");
if (System.IO.File.Exists(filePath))
{
// File exists
}
else
{
// File doesn't exist
}
I'm doing a Win10 IoT Core UWP app and I have to check the file length instead of "Exists" because CreateFileAsync() already creates an empty file stub immediately. But I need that call before to determine the whole path the file will be located at.
So it's:
var destinationFile = await ApplicationData.Current.LocalFolder.CreateFileAsync("MyFile.wow", ...);
if (new FileInfo(destinationFile.Path).Length > 0)
return destinationFile.Path;
In this way System.IO.File.Exists(filePath) I cannot test DocumentLibrary
because KnownFolders.DocumentsLibrary.Path return empty string
Next solution is very slow await DownloadsFolder.GetFileAsync("01-Introduction.pdf")
IMHO the best way is collect all files from folder and check the file name exist.
List<StorageFile> storageFileList = new List<StorageFile>();
storageFileList.AddRange(await KnownFolders.DocumentsLibrary.GetFilesAsync(CommonFileQuery.OrderByName));
bool fileExist = storageFileList.Any(x => x.Name == "01-Introduction.pdf");
CreateFileSync exposes an overload that let's you choose what to do if an existing file with the same name has been found in the directory, as such:
StorageFile localDbFile = await DownloadsFolder.CreateFileAsync(LocalDbName, CreationCollisionOption.OpenIfExists);
CreationCollisionOption is the object that you need to set up. In my example i'm opening the file instead of creating a new one.
Based on another answer here, I like
public static async Task<bool> DoesFileExist(string filePath) {
var directoryPath = System.IO.Path.GetDirectoryName(filePath);
var fileName = System.IO.Path.GetFileName(filePath);
var folder = await StorageFolder.GetFolderFromPathAsync(directoryPath);
var file = await folder.TryGetItemAsync(fileName);
return file != null;
}
You can use the FileInfo class in this case. It has a method called FileInfo.Exists() which returns a bool result
https://msdn.microsoft.com/en-us/library/system.io.fileinfo.exists(v=vs.110).aspx
EDIT:
If you want to check for the files existence, you will need to create a StorageFile object and call one of the GetFile.... methods. Such as:
StorageFile file = new StorageFile();
file.GetFileFromPathAsync("Insert path")
if(file == null)
{
/// File doesn't exist
}
I had a quick look to find the download folder path but no joy, but the GetFile method should give you the answer your looking for
On Window 10, for me, this is the most "elegant" way:
private static bool IsFileExistent(StorageFile file)
{
return File.Exists(Path.Combine(file.Path));
}
Or, as an extension if you prefer and will use it widely:
static class Extensions
{
public static bool Exists(this StorageFile file)
{
return File.Exists(Path.Combine(file.Path));
}
}
Related
I have a problem with creating folder with nuget package PCLStorage, I cannot create folder.
Nothing appear inside my files folder. I,m using my device not emulator there is android version 8.0
public async Task WriteDataAsync(string filename, string data)
{
string folderName = "SignatureSotrage";
IFolder folder = FileSystem.Current.LocalStorage;
folder = await folder.CreateFolderAsync(folderName, CreationCollisionOption.ReplaceExisting);
}
Here is a code where I run this function:
public ICommand AddCustomerCommand => new Command(async () =>
{
Signature = await SignatureFromStream();
// Signature should be != null
var customer = new Customer()
{
FullName = this.FullName,
IsAccepted = this.IsAccepted,
Birthday = this.Birthday
};
if(Signature != null)
{
customer.Image = this.Signature.ToString();
}
else
{
await Application.Current.MainPage.DisplayAlert("Błąd", "Nie wszystkie pola zostały poprawnie wypełnione", "OK");
return;
}
await DependencyService.Get<IFileHelper>().WriteDataAsync("signature.txt", "this is file");
//_context.Customers.Add(customer);
//_context.SaveChanges();
});
did you debug your code & check if the file/folder is actually getting created by your code or else it enters the catch block and goes with the normal flow?
Check for UserPermissions every time for reading & write permission before doing any operations on the storage. You can add the Nugget packet Plugin.Permission it handles everything for you, it adds both the permission in the manifest.
For checking user permissions always try calling CheckForStoragePermissions() before performing any operations on storage.(*DialogService is CustomDialogBox)
if( !await CheckForStoragePermissions() )
{
DialogService.Alert("Invalid Permission", "User declined permission for this action");
return;
}
private async Task<bool> CheckForStoragePermissions()
{
PermissionStatus storagePermissionStatus = await CrossPermissions.Current.CheckPermissionStatusAsync(Permission.Storage);
if (storagePermissionStatus != PermissionStatus.Granted)
{
Dictionary<Permission, PermissionStatus> storagePermissionResult = await CrossPermissions.Current.RequestPermissionsAsync(Permission.Storage);
if (storagePermissionResult.ContainsKey(Permission.Storage))
{
storagePermissionStatus = storagePermissionResult[Permission.Storage];
}
}
return storagePermissionStatus == PermissionStatus.Granted;
}
I test the sample code on GitHub. https://github.com/dsplaisted/PCLStorage
Based on my test the folder path would like:
/data/user/0/PCLStorage.Test.Android/files/
It is a internal storage. You couldn't see the files without root permission. https://learn.microsoft.com/en-us/xamarin/android/platform/files/#working-with-internal-storage
If you want to see the files in internal storage, you could use adb tool. Please refer to the way in the link. How to write the username in a local txt file when login success and check on file for next login?
I cannot read nlog.config file in asset folder of android platform
NLog.LogManager.Configuration = new XmlLoggingConfiguration("NLog.config");
How to read nlog file and also this file is in android asset.
You can also make use of Xamarin resource. Put the NLog.config file into the library project, then edit file's properties - change the build action to embedded resource.
public static Stream GetEmbeddedResourceStream(Assembly assembly, string resourceFileName)
{
var resourcePaths = assembly.GetManifestResourceNames()
.Where(x => x.EndsWith(resourceFileName, StringComparison.OrdinalIgnoreCase))
.ToList();
if (resourcePaths.Count == 1)
{
return assembly.GetManifestResourceStream(resourcePaths.Single());
}
return null;
}
var nlogConfigFile = GetEmbeddedResourceStream(myAssembly, "NLog.config");
if (nlogConfigFile != null)
{
var xmlReader = System.Xml.XmlReader.Create(nlogConfigFile);
NLog.LogManager.Configuration = new XmlLoggingConfiguration(xmlReader, null);
}
See also: https://github.com/NLog/NLog/wiki/Explicit-NLog-configuration-loading#loading-nlog-configuration-from-xamarin-resource
you could also try to use this (nlog.config file with a Build Action as an AndroidAsset):
NLog.LogManager.Configuration = new XmlLoggingConfiguration (XmlTextReader.Create(Assets.Open ("NLog.config")), null);
refer to:
https://github.com/NLog/NLog/blob/master/src/NLog/Config/LoggingConfigurationFileLoader.cs#L101-L120
You can add an extension method to your context class that gets you the required asset as a stream:
public static class Utils
{
public static Stream GetFromAssets(this Context context, string assetName)
{
AssetManager assetManager = context.Assets;
Stream inputStream;
try
{
using (inputStream = assetManager.Open(assetName))
{
return inputStream;
}
}
catch (Exception e)
{
return null;
}
}
}
And then in your activity context access it like:
var Asset= context.GetFromAssets("AssetName");
Note that this will return a System.IO.Stream.
Good luck
Revert in case of queries.
For Xamarin Android "NLog.config" (in this casing) in the assets folder will be loaded automatically. If the file name is different, then use:
LogManager.Configuration = new XmlLoggingConfiguration("assets/someothername.config");
Thanks for your response. I resolved this issue by setting autoReload="false" throwExceptions="false". Due to these two my config file was not visible. I dont know how they affect the file visibility but setting above two to false i can get config file now
Thanks,
I have a problem coping a file. I need to copy a .db file and put it in a new folder (called "directory",selected previously with FolderPicker).
The code that i have is: (this is for a store app for Windows 8.1)
try{
StorageFile newDB = await StorageFile.GetFileFromPathAsync(directory);
StorageFile originalDB = await StorageFile.GetFileFromPathAsync(Path.Combine(Windows.Storage.ApplicationData.Current.LocalFolder.Path, "AFBIT.db"));
await newDB.CopyAndReplaceAsync(originalDB);
}
catch(Exception ex){
}
I have a exception in neDB, and said "Value does not fall within the expected range."
I dont know another way to copy a file in xaml, if u know what is the problem or another way to do this i llbe very grateful.
I have something similar that I currently use when copying a file CopyFileAsync method I have created see if this can help you in regards to refactoring your code to a working model
public static async Task CopyFileAsync(string sourcePath, string destinationPath)
{
try
{
using (Stream source = File.Open(sourcePath, FileMode.Open))
{
using (Stream destination = File.Create(destinationPath))
{
await source.CopyToAsync(destination);
}
}
}
catch (IOException io)
{
HttpContext.Current.Response.Write(io.Message); //I use this within a web app change to work for your windows app
}
}
I'm not sure what your truly inquiring but I believe your attempting is:
public static bool CopyFile(string source, string destination)
{
if(!File.Exist(source))
return false;
if(string.IsNullOrEmpty(destination))
return false;
try
{
using(var reader = File.Open(source))
using(var writer = File.Create(destination))
reader.CopyTo(writer);
return true;
}
catch(IOException ex) { return false; }
}
Bare in mind this will eat your exception, then return false if it fails at any point for any reason.
That would essentially copy the file, I noticed that your trying to read your local application folder. Be careful, as it often requires Administrator Privileges when it resides in several locations within the Operating System.
I'm having some problems. Here's my code:
private async void SetCollectionForGame()
{
maincollection = new Dictionary<string, string>();
bool statebase = await CheckExistingBase();
if (statebase)
{
//If file exists...
basefile = await folder.GetFileAsync(basefilename);
}
else
{
//If file does not exist...
SaveBaseFileAsync(filelink, folder, basefilename);
basefile = await folder.GetFileAsync(basefilename);
}
string content = String.Empty;
content = await FileIO.ReadTextAsync(basefile, Windows.Storage.Streams.UnicodeEncoding.Utf8);
//When the app first starts, I get an exception on the next line,
//because the variable "content" is null.
maincollection = JsonConvert.DeserializeObject<CollectionModel>(content).collection;
}
Does anybody know how to solve this? File downloading works fine, and after the download the file was created in a folder.
Based on the name, I suspect that SaveBaseFileAsync() executes some async operations. If it's true, you need to await it, i.e. call it as
await SaveBaseFileAsync(filelink, folder, basefilename);
This question already has answers here:
How to check if file exists in a Windows Store App?
(10 answers)
Closed 9 years ago.
While making a lab on window 8 app dev. I could not load all images needed. So inorder for the share part to work with a sharing imag I need to check if the image file is availeble.
The project is a windows grid app using XAML and C#
In the past I used
Using System.IO
... lost of code
privat void share()
....
if (File.exist(filename)
{
add file to share
}
If i try this in my window8 project. The File class is not found.
I search the internet but could not find a code example that checkes the existance in a windowsstore app in C#
Michiel
you need StorageFile not File
here is simple example to check and get the file
StorageFile file;
try {
file = await ApplicationData.Current.LocalFolder.GetFileAsync("foo.txt");
}
catch (FileNotFoundException) {
file = null;
}
you can write a function
public static async Task<bool> FileExistsAsync(this StorageFolder folder, string fileName)
{
try
{
await folder.GetFileAsync(fileName);
return true;
}
catch (FileNotFoundException)
{
return false;
}
}
If you know the path in your local storage and you have a bunch of files to check, you can do the following...
var sourceFolder = Windows.ApplicationModel.Package.Current.InstalledLocation;
sourceFolder = await sourceFolder.GetFolderAsync("Assets");
var files = await sourceFolder.GetFilesAsync();
var requiredFiles = new List<String> { "ThisWorks.png", "NotHere.png" };
foreach(var filename in requiredFiles)
{
// your example logic here...
Debug.WriteLine(filename + " " + (files.Any(f => f.Name == filename) ? "Exists" : "Doesn't exist"));
}