I am trying to, in some instances, read from, and in others, write to a file in Windows Phone 8.1. I am using the following code to read it:
var folder = ApplicationData.Current.LocalFolder;
try
{
var connectionsFile = await folder.OpenStreamForReadAsync("connections");
using (var streamReader = new StreamReader(connectionsFile, Encoding.Unicode))
{
while (!streamReader.EndOfStream)
{
String con = await streamReader.ReadLineAsync();
String[] props = con.Split('\t');
Connection newConnection = new Connection() { Name = props[0], Url = props[1] };
ConnectionsCollection.Add(newCollection);
}
await connectionsFile.FlushAsync();
connectionsFile.Dispose();
}
}
catch(Exception e)
{
//handle exception
}
My problem is that it unfailingly hits the catch with an inner exception of "The handle with which this oplock was associated has been closed. The oplock is now broken." (I get the same error when trying to write to it.) I can't figure out what the problem is, especially since I am successfully using the same code to read the same file in two other places.
I think you needs to remove the await connectionsFile.FlushAsync(); line because you're using the file for reading. Also remove the connectionsFile.Dispose(); and use the using(...) in connectionsFile assignment.
var folder = ApplicationData.Current.LocalFolder;
try
{
using (var connectionsFile = await folder.OpenStreamForReadAsync("connections"))
using (var streamReader = new StreamReader(connectionsFile, Encoding.Unicode))
{
while (!streamReader.EndOfStream)
{
String con = await streamReader.ReadLineAsync();
String[] props = con.Split('\t');
Connection newConnection = new Connection() {Name = props[0], Url = props[1]};
ConnectionsCollection.Add(newCollection);
}
}
}
catch (Exception e)
{
//handle exception
}
I hope it helps.
Related
I'm working on an ASP.NET Core 5 project. I have this action method:
public async Task<IActionResult> CreateV3EnterCheckFile(IFormFile MarksFile)
{
var filesCount = Directory.GetFiles("Uploads").Length;
string path = Path.Combine("Uploads", filesCount + 1 + ".xlsx");
await MarksFile.SaveToAsync(path);
var xlImporter = new XLImporter();
var importedData = await xlImporter.ImportSheetAsync(path, 0);
var r = (from x in importedData select new { ID = x[0], StudentId = x[1] }).ToList();
System.IO.File.Delete(path);
return View();
}
I tried to get IFormFile uploaded file by the user to save it on the server and querying it using one of my projects (that uses LinqToExcel library).
I am querying the data and everything is perfect I still have just one problem it is this line of code:
System.IO.File.Delete(path);
It throws an exception and the message is I can't delete that file because it is still being used by another process.
I'm very sure that the process is related to the LinqToExcel library.
More details :
SaveToAsync is an extension method created by me that is its definition
public static Task SaveToAsync(this IFormFile file, string pathToSaveTo)
{
return Task.Factory.StartNew(() =>
{
using (Stream fileStream = File.Open(pathToSaveTo, FileMode.Create, FileAccess.ReadWrite, FileShare.None))
{
file.CopyTo(fileStream);
}
});
}
Please - is there any way or method or solution to delete this file even if it is being used by another process?
Massive thanks in advance.
Based on the source code of ExcelQueryFactory (https://github.com/paulyoder/LinqToExcel/blob/master/src/LinqToExcel/ExcelQueryFactory.cs) I would try the following:
ExcelQueryFactory has a ReadOnly Property. For read only access (if applicable) I would set it to true when creating the instance.
More important: IExcelQueryFactory implements IDisposable, so you can (should) use a using block:
using (var excelFile = new ExcelQueryFactory(pathToExcelFile) {ReadOnly = true})
{
// Do your work.
}
Of course you can use using var ..., but if you need a more reduced scope, the "old" using syntax allows more control.
I assumed that your Uploads folder is under webroot.
You can try this:-
public YourControllerName(IHostingEnvironment he) //input parameter
{
_he = he;
}
public async Task<IActionResult> CreateV3EnterCheckFile(IFormFile MarksFile)
{
try
{
var filesCount = Directory.GetFiles("Uploads").Length;
string contentRootPath = _he.ContentRootPath;
string path = Path.Combine(contentRootPath +"\\Uploads", filesCount + 1 + ".xlsx");
await MarksFile.SaveToAsync(path);
var xlImporter = new XLImporter();
var importedData = await xlImporter.ImportSheetAsync(path, 0);
var r = (from x in importedData select new { ID = x[0], StudentId = x[1] }).ToList();
//System.IO.File.Delete(path);
if (File.Exists(path))
{
File.Delete(path);
}
else
{
Debug.WriteLine("File does not exist.");
}
return View();
}
catch(Exception e)
{
Console.WriteLine(e);
}
Or you can try another process:-
try
{
System.GC.Collect();
System.GC.WaitForPendingFinalizers();
System.IO.File.Delete(path);
}
catch(Exception e){
}
}
Or this:-
if (System.IO.File.Exists(path))
{
try
{
System.GC.Collect();
System.GC.WaitForPendingFinalizers();
System.IO.File.Delete(path);
}
catch (Exception e) { }
}
it should resolve your issue I hope. by the way, if your Upload folder is not under the webroot path. you can find your path using your process.
Previously, I developed an application which downloaded a file from a corporate Sharepoint site and then performed some magic with it.
The powers that be have since migrated to MS Teams and I'm trying to update the application to use the new platform. However, I'm having all sorts of issues getting the file to download.
My old (working for Sharepoint) code uses a WebClient to retrieve the file based on credentials previously provided by the user:
private string GetSchedule(string username, string password, string domain)
{
string tempPath = Path.GetTempFileName().Replace(".tmp", ".xlsm");
using (WebClient client = new WebClient())
{
client.Credentials = new NetworkCredential(username, password, domain);
try
{
client.DownloadFile(_networkSchedulePath, tempPath);
}
catch (WebException e)
{
if (e.Message.Contains("401"))
{
StatusUpdated?.Invoke(this, new EventArgs<string>("Invalid Credentials Provided"));
Finished?.Invoke(this, null);
return null;
}
if (e.Message.Contains("404"))
{
StatusUpdated?.Invoke(this, new EventArgs<string>("File Not Found"));
Finished?.Invoke(this, null);
return null;
}
else
{
StatusUpdated?.Invoke(this, new EventArgs<string>(e.Message));
Finished?.Invoke(this, null);
return null;
}
}
}
return tempPath;
}
However, when I use this with the new teams link I'm getting a 403 Forbidden error. So is there any way to programmatically retrieve a file from MS Teams?
I was mistaken in the comments. Simply replacing the NetworkCredentials with SharePointOnlineCredentials is not the solution.
I'm not sure if the following is the "right" approach, but it works and seems pretty solid. Please give it a try:
private static string GetFile(string path, string username, string password, string domain)
{
var secureString = new SecureString();
foreach (var ch in password)
{
secureString.AppendChar(ch);
}
string tempPath = Path.GetTempFileName().Replace(".tmp", ".xlsm");
using (WebClient client = new WebClient())
{
var credentials = new SharePointOnlineCredentials(username, secureString);
client.Headers[HttpRequestHeader.Cookie] = credentials.GetAuthenticationCookie(new Uri(path));
try
{
client.DownloadFile(path, tempPath);
}
catch (WebException e)
{
// Error Handling
}
}
return tempPath;
}
Another option is to use the CSOM rather than using a webclient directly. n.b., I encountered errors at the OpenBinaryDirect() call when using the Microsoft.SharePoint.Client NuGet package and it looks like this package is wildly out of date. It appears that the one to use now is Microsoft.SharePointOnline.CSOM or Microsoft.SharePoint2019.CSOM:
private static string GetFileWithClientContext(string path, string username, string password, string domain)
{
var secureString = new SecureString();
foreach (var ch in password)
{
secureString.AppendChar(ch);
}
string tempPath = Path.GetTempFileName().Replace(".tmp", Path.GetExtension(path));
using (var context = new ClientContext(path))
{
context.Credentials = new SharePointOnlineCredentials(username, secureString);
try
{
using (var file = Microsoft.SharePoint.Client.File.OpenBinaryDirect(context, new Uri(path).AbsolutePath))
using (var outFile = System.IO.File.OpenWrite(tempPath))
{
file.Stream.CopyTo(outFile);
}
}
catch (WebException e)
{
// Error Handling
}
}
return tempPath;
}
Thanks to JLRishe for the help his answer and comments provided. However, the final solution varied from the one in his answer, which is why I'm posting it here:
The OfficeDevPnP.Core package is used extensively for this.
Firstly, the AuthenticationManager is used to get a ClientContext in terms of the specific sharepoint site that needs to be accessed. This pops a window up to allow for the MFA. Then various components are loaded in via the ClientContext object. From here, the file is fetched via Guid and dumped to disk.
private string GetSchedule()
{
string tempPath = Path.GetTempFileName().Replace(".tmp", ".xlsm");
try
{
AuthenticationManager authManager = new OfficeDevPnP.Core.AuthenticationManager();
ClientContext ctx = authManager.GetWebLoginClientContext("https://oursite.sharepoint.com/sites/ourspecificsite/");
Web web = ctx.Web;
Microsoft.SharePoint.Client.File schedule = web.GetFileById(new Guid("ourguid"));
ctx.Load(web);
ctx.Load(schedule);
ctx.ExecuteQuery();
FileInformation fInfo = Microsoft.SharePoint.Client.File.OpenBinaryDirect(ctx, schedule.ServerRelativeUrl);
using (var fileStream = File.Create(tempPath))
{
fInfo.Stream.CopyTo(fileStream);
}
}
catch (WebException e)
{
StatusUpdated?.Invoke(this, new EventArgs<string>(e.Message));
return null;
}
return tempPath;
}
using Microsoft.Graph;
using Microsoft.Graph.Auth;
using Microsoft.Identity.Client;
using System.IO;
using System.Linq;
namespace Answer
{
class Answer
{
static void Main(string[] args)
{
// Create Confidential Application
IConfidentialClientApplication confidentialClientApplication = ConfidentialClientApplicationBuilder
.Create("<My_Azure_Application_Client_ID>")
.WithTenantId("<My_Azure_Tenant_ID>")
.WithClientSecret("<My_Azure_Application_Client_Secret>")
.Build();
// Create an authentication provider.
ClientCredentialProvider authenticationProvider = new ClientCredentialProvider(confidentialClientApplication);
// Configure GraphServiceClient with provider.
GraphServiceClient graphServiceClient = new GraphServiceClient(authenticationProvider);
// Get a user
var user = graphServiceClient.Users["<My_Azure_User_Name>"].Request().GetAsync().Result;
// Get the teams the user is member of
var joinedTeams = graphServiceClient.Users[user.Id].JoinedTeams.Request().GetAsync().Result;
// Get the team we are intereseted in
var team1 = joinedTeams.FirstOrDefault(t => t.DisplayName == "<TeamName_Of_Interest>");
// Get the main folders
var folders = graphServiceClient.Groups[team1.Id].Drive.Root.Children
.Request()
.GetAsync().Result;
// Get the files in the first main folder
var files = graphServiceClient.Groups[team1.Id].Drive.Items[folders[0].Id].Children
.Request()
.GetAsync().Result;
// Get the file-Data of the first file
MemoryStream fileData = graphServiceClient.Groups[team1.Id].Drive.Items[files[0].Id].Content
.Request()
.GetAsync().Result as MemoryStream;
// Save the file to the hard-disc
System.IO.File.WriteAllBytes($"C:\\{files[0].Name}", fileData.ToArray());
}
}
}
I had this piece of code that initially worked fine. However, After adding it to a class where I store my methods that are reused, it keeps failing. The exception that is caught states that the CancellationTokenSource has been Disposed. Can someone point me in the right direction?
I have tried creating a new client and Adding CancellationToken.None to the PutAsync() method from HTTPClient Class but it still fails with the CancellationTokenSource Disposed exception.
public async void AddProduct(Product product)
{
string storeId = "";
try
{
var storeData = JObject.Parse(Connect.Json).SelectToken("store").ToString();
var stores = JsonConvert.DeserializeObject<List<Store>>(storeData);
var store = stores[0];
storeId = store.Id;
store.Products.Add(product);
ProdInfo info = new Info();
foreach(Product p in store.Products)
{
info.AddedProducts = + p.Id;
}
var content = JsonConvert.SerializeObject(info);
using (Connect.Client)
using (var response = await Connect.Client.PutAsync(_url + "/stores/" + storeId, new StringContent(content)))
{
var cont = response.Content;
string result = await cont.ReadAsStringAsync();
if ((int)response.StatusCode == 200)
{
this.JobResult = result;
//this.JobResult = "Store has been successfully updated";
}
else
{
this.JobResult = result;
//this.JobResult = "Store was not updated!";
}
}
}
catch (Exception ex)
{
//this.JobResult = "Store has not been updated due to an error.";
this.JobResult = ex.Message;
}
}
I was able to solve this by simple removing 'using(Connect.Client)' from all of my methods. As #sellotape stated, They were disposing of the HttpClient before I was able to use it again. Thank you all for your contributions.
look for this error and tell me your opinion to solve this problem
I was making window phone Application :
its can't save my picked file in a storage file to trim it as media
or I can not relate between open file picker and storage file if anyone have any ideas how to relate between them or have any demos please tell me
I'm not sure I understood your problem. Here is my code for picking a file and write into it in WinRT/Win10 store app.
private async void SaveFileExecute()
{
var fileNameTab = FileName.Split('.');
var extension = fileNameTab[1];
var fileName = fileNameTab[0];
var savePicker = new FileSavePicker
{
SuggestedStartLocation = PickerLocationId.DocumentsLibrary,
SuggestedFileName = fileName
};
savePicker.FileTypeChoices.Add(extension, new List<string> { "." + extension });
var saveFile = await savePicker.PickSaveFileAsync();
if (saveFile != null)
{
using (var fileStream = await saveFile.OpenAsync(FileAccessMode.ReadWrite))
{
using (var outputStream = fileStream.GetOutputStreamAt(0))
{
using (var dataWriter = new DataWriter(outputStream))
{
dataWriter.WriteBytes(SelectedFile.Data);
await dataWriter.StoreAsync();
dataWriter.DetachStream();
}
await outputStream.FlushAsync();
}
}
}
}
I am trying to retrieve items from an rss feed but at times I get a TargetInvocationException 'unable to connect to remote server'. I am trying to use a try catch block to catch this error but I am not managing as I need the variable feed to be used throughout the other code and like this it is not visible. Any suggestions?
public static async Task<List<FeedItem>> getFeedsAsync(string url)
{
//The web object that will retrieve our feeds..
SyndicationClient client = new SyndicationClient();
//The URL of our feeds..
Uri feedUri = new Uri(url);
//Retrieve async the feeds..
try
{
var feed = await client.RetrieveFeedAsync(feedUri);
}
catch (TargetInvocationException e)
{
}
//The list of our feeds..
List<FeedItem> feedData = new List<FeedItem>();
//Fill up the list with each feed content..
foreach (SyndicationItem item in feed.Items)
{
FeedItem feedItem = new FeedItem();
feedItem.Content = item.Summary.Text;
feedItem.Link = item.Links[0].Uri;
feedItem.PubDate = item.PublishedDate.DateTime;
feedItem.Title = item.Title.Text;
try
{
feedItem.Author = item.Authors[0].Name;
}
catch(ArgumentException)
{ }
feedData.Add(feedItem);
}
return feedData;
}
}
}
This kind of error cannot be prevented. It is an exogenous exception.
There is only one way to deal with those kinds of errors: your application must be designed to expect them and react in a reasonable way (e.g., bring up an error dialog or notification).
In particular, don't try to ignore them with an empty catch block.
IAsyncOperationWithProgress<SyndicationFeed, RetrievalProgress> feed;
//Retrieve async the feeds..
try
{
feed = await client.RetrieveFeedAsync(feedUri);
}
catch (TargetInvocationException e)
{
}