I need to read csv file twice. but after first reading:
using (var csvReader = new StreamReader(file.InputStream))
{
fileFullText += csvReader.ReadToEnd();
file.InputStream.Seek(0, SeekOrigin.Begin);
csvReader.Close();
}
using file in enother function:
public static List<string> ParceCsv(HttpPostedFileBase file)
{
//file.InputStream.Seek(0, SeekOrigin.Begin);
using (var csvReader = new StreamReader(file.InputStream))
{
// csvReader.DiscardBufferedData();
// csvReader.BaseStream.Seek(0, SeekOrigin.Begin);
string inputLine = "";
var values = new List<string>();
while ((inputLine = csvReader.ReadLine()) != null)
{
values.Add(inputLine.Trim().Replace(",", "").Replace(" ", ""));
}
csvReader.Close();
return values;
}
}
The file.Length is 0.
Can anybody help?
The reason is that SteramReader's Dispose() method also closes the underlying stream; In your case file.InputStream. The using statement calls Dispose() implicitly. Try to replace using with disposes of both your StreamReaded-s after you finished both read operations. As I remember some stream classes have a bool option to leave underlying stream open after dispose.
.NET 4.5 fixed this issue by introducing leaveOpen parameter in SteamReader constructor. See: MSDN
public StreamReader(
Stream stream,
Encoding encoding,
bool detectEncodingFromByteOrderMarks,
int bufferSize,
bool leaveOpen
)
One more thing. You do not need to close SteramReader yourself (the line with csvReader.Close();) when you wrap it in using statement, thus Dispose() and Close() are the same in case of StreamReader.
if your using HttpPostedFileBase you need to clone it first,
use the code this git here
or just add this as a class in your namespace:
public static class HttpPostedFileBaseExtensions
{
public static Byte[] ToByteArray(this HttpPostedFileBase value)
{
if (value == null)
return null;
var array = new Byte[value.ContentLength];
value.InputStream.Position = 0;
value.InputStream.Read(array, 0, value.ContentLength);
return array;
}
}
now you can read the HttpPostedFileBase like so:
private static void doSomeStuff(HttpPostedFileBase file)
{
try
{
using (var reader = new MemoryStream(file.ToByteArray()))
{
// do some stuff... say read it to xml
using (var xmlTextReader = new XmlTextReader(reader))
{
}
}
}
catch (Exception ex)
{
throw ex;
}
}
after using this you can still write in your main code:
file.SaveAs(path);
and it will save it to the file.
Related
I am creating a program which takes passwords and applies an encoding on them onto a file which I have creatively labeled a PASSWORDFILE file. I am a self taught amateur programmer and this is my first time using streams => I'm sorry my code isn't cleaner. When I add a password to my file, the file refuses to open (giving me a "System.IO.IOException: The process cannot access the file '[file path here]' because it is being used by another process."). I have made sure I am closing all my streams yet this error still persists.
To add further confusion:
namespace PasswordSaver
{
[Serializable]
class Password
{
public string ID;
string baseWord;
public Password(string password, string ID)
{
this.ID = ID;
baseWord = password;
}
public virtual string GetPassword()
{
return baseWord;
}
}
[Serializable]
class EncodedPassword : Password
{
EncoderAndDecoder Encoder;
public EncodedPassword(string decodedBasePassword, string ID) : base(decodedBasePassword, ID)
{
Encoder = new EncoderAndDecoder();
}
public override string GetPassword()
{
return Encoder.Encode(base.GetPassword(), out _);
}
}
[Serializable]
class EncodedPasswordWithAddendum : EncodedPassword
{
string addendum;
public EncodedPasswordWithAddendum(string decodedBasePassword, string addendum, string ID) : base(decodedBasePassword, ID)
{
this.addendum = addendum;
}
public override string GetPassword()
{
return base.GetPassword() + addendum;
}
}
}
the error only occurs when I attempt to add an EncodedPassword or EncodedPasswordWithAddendum instances but not a Password instance.
My writing code is
namespace PasswordSaver
{
class PasswordWriter
{
public readonly string saveFilePath;
static string directory = Directory.GetCurrentDirectory();
#region Constructors
public PasswordWriter()
{
saveFilePath = directory + #"\PasswordSaver"
+ ".passwordfile";
}
public PasswordWriter(string saveFilePath)
{
this.saveFilePath = saveFilePath;
}
#endregion
#region Individual Writing Functions
private void WriteBinary(object objectToEncode)
{
WriteBinary(objectToEncode, out _);
}
private void WriteBinary(object objectToEncode, out Exception exception)
{
exception = null;
try
{
IFormatter binaryFormatter = new BinaryFormatter();
Stream fileStream = new FileStream(saveFilePath, FileMode.OpenOrCreate, FileAccess.ReadWrite);
Stream memoryStream = new MemoryStream();
memoryStream.Position = memoryStream.Length;
binaryFormatter.Serialize(memoryStream, objectToEncode);
EncodeFromStream(ref memoryStream, ref fileStream);
fileStream.Close();
memoryStream.Close();
}
catch (Exception e)
{
exception = e;
}
}
#endregion
#region File Read and Writing
public void WriteFile(Password[] passwords)
{
if (File.Exists(saveFilePath))
{
Stream stream = new FileStream(saveFilePath, FileMode.Truncate, FileAccess.Write);
stream.Close();
}
WriteBinary(passwords.Length);
foreach (Password password in passwords)
{
WriteBinary(password);
}
}
public void WriteToFile(Password password)
{
Password[] oldPasswords = ReadFile();
Password[] passwords = new Password[oldPasswords.Length + 1];
for (int i = 0; i < oldPasswords.Length; i++)
{
passwords[i] = oldPasswords[i];
}
passwords[oldPasswords.Length] = password;
WriteFile(passwords);
}
public bool ReplacePassword(string oldPasswordID, Password newPassword)
{
Password[] passwords = ReadFile();
for (int i = 0; i < passwords.Length; i++)
{
if (passwords[i].ID == oldPasswordID)
{
passwords[i] = newPassword;
return true;
}
}
return false;
}
public Password[] ReadFile()
{
Stream fileStream = new FileStream(saveFilePath, FileMode.OpenOrCreate, FileAccess.Read);
IFormatter binaryFormatter = new BinaryFormatter();
Stream memoryStream = new MemoryStream();
DecodeFromStream(ref fileStream, ref memoryStream);
fileStream.Close();
memoryStream.Position = 0;
int length = (int) binaryFormatter.Deserialize(memoryStream);
//Console.WriteLine(length + " is the length");//debug
Password[] passwords = new Password[length];
for (int i = 0; i < length; i++)
{
//Console.WriteLine(memoryStream.Position + " " + memoryStream.Length);//debug
//Console.WriteLine(i);//debug
passwords[i] = (Password)binaryFormatter.Deserialize(memoryStream);
}
memoryStream.Close();
return passwords;
}
#endregion
#region Encode and Decode
private void EncodeFromStream(ref Stream stream, ref Stream newStream)
{
stream.Position = 0;
newStream.Position = newStream.Length;
for (int i = 0; i < stream.Length; i++)
{
int integer = stream.ReadByte();
byte originalByte = (byte)integer;// get a byte off of the line
//Encode byte here
newStream.WriteByte(setOfBits1);
newStream.WriteByte(setOfBits2);
}
}
private void DecodeFromStream(ref Stream stream, ref Stream newStream)
{
newStream.Position = newStream.Length;
stream.Position = 0;
for (int i = 0; i < (stream.Length / 2); i++)// stream.Length / 2 because the program reads two bytes per iteration of the for loop
{
//I decode the bytes here
newStream.WriteByte(originalByte);
}
}
#endregion
public void WriteContentsToFile()
{
Stream stream = new FileStream(saveFilePath + "1", FileMode.OpenOrCreate, FileAccess.ReadWrite);
Stream stream1 = new FileStream(saveFilePath, FileMode.OpenOrCreate, FileAccess.ReadWrite);
this.DecodeFromStream(ref stream1, ref stream);
stream.Close();
stream1.Close();
}
}
}
I have removed the code that encoded and decoded the streams in EncodeFromStream and DecodeFromStream.
any occurrence of new FileStream(saveFilePath + "1", FileMode.OpenOrCreate, FileAccess.ReadWrite) is a where I was writing to a seperate file in a decoded format. To distinguish the two files I changed the file type from PASSWORDFILE to PASSWORDFILE1.
In Conclusion:
I am using the WriteFile or WriteToFile methods with a Password[] that contains an EncodedPassword or EncodedPasswordWithAddendum. then when I try to open the file through a FileStream (usually through the method ReadFile) I get the Exception "System.IO.IOException: The process cannot access the file '[file path here]' because it is being used by another process".
Thank you for your help.
Streams usually contain unamanged resources (the OS Filehandles), so they implement IDisposeable.
While you can always be certain that the GC will clean up disposeable stuff eventually (latest at application closing), usually that is way to late. You have to do it explicitly. And for that I have a one rule regarding IDisposeable stuff:
"Never split up the creation and disposing of a disposeable resource. Create. Use. Dispose. All in the same piece of code, ideally using a using block."
The only exception I ever encountered a logfiles. Nothing else is remotely worth the trouble and headaches of keeping something disposeable open. Especially not performance.
As the using block uses a try...finally, you can be certain it will run. Compiler and runtime make certain finally blocks always run, even on function return, jump via goto or Exception cases.
I need to pass a stream to a couple of functions in another class, but its throwing an error
Cannot access a closed stream
Here's the code:
first method:
Here it opens a file with File.Open method and then creates a memorystream object and it copies FileStream to MemoryStream. then sets Position to 0 (i set position to 0, because i was that in a solution, but not helping tho). Then it creates an object of class DocxConvert and call the Converto method by passing MemoryStream to it.
using (var stream = File.Open(tempPath2, FileMode.Open))
{
using(var ms = new MemoryStream())
{
stream.CopyTo(ms);
ms.Position = 0;
using (var docx = new DocxConvert())
{
return docx.Converto(ms);
}
}
}
DocxConvert Class:
It takes stream and then calls copyStream method by passing the accepted stream.
copyStream method in DocxConvert Class: it should copy the accepted stream to another stream called _memoryStream which is a class property.
public class DocxConvert
{
private MemoryStream _memoryStream = new MemoryStream();
public bool Converto(Stream stream)
{
try
{
copyStream(stream);
//more code
}
catch (IOException ex)
{
Debug.WriteLine(ex);
}
return true;
}
private void copyStream(Stream stream)
{
stream.CopyTo(_memoryStream); //here it throws the error
}
}
p.s. I search for this error here before posting, but non of the topics helped me.
SOLVED by restarting PC, the code it ok.
I am not aware about your question .But here in the code bellow no excepion
private void button1_Click(object sender, EventArgs e)
{
string tempPath2 = Application.StartupPath + "//" + "test.txt";
using (var stream = File.Open(tempPath2, FileMode.Open))
{
using (var ms = new MemoryStream())
{
stream.CopyTo(ms);
ms.Position = 0;
var docx = new DocxConvert();
var isok = docx.Converto(ms);
}
}
}
The bellow is the calss defined where _memorystream is defined at top
MemoryStream _memoryStream = new MemoryStream();
public bool Converto(Stream stream)
{
try
{
copyStream(stream);
//more code
}
catch (IOException ex)
{
// Debug.WriteLine(ex);
}
return true;
}
private void copyStream(Stream stream)
{
try
{
stream.CopyTo(_memoryStream);
}
catch (Exception)
{
}
}
I have the following code that generate two kinds of errors. First with the current code I get an exception 'NotSupportedException: This stream from ZipArchiveEntry does not support reading.'. How am I supposed to read the data ?
Furthermore if i use a MemoryStream (as the commented code ) then I can read the data and deserialize correctly but the memorystream i created still remains in memory even if the dispose method has been called on it , causing some memory leaks . Any idea what is wrong with this code ?
void Main()
{
List<Product> products;
using (var s = GetDb().Result)
{
products = Utf8Json.JsonSerializer.Deserialize<List<Product>>(s).ToList();
}
}
// Define other methods and classes here
public static Task<Stream> GetDb()
{
var filepath = Path.Combine("c:/users/tom/Downloads", "productdb.zip");
using (var archive = ZipFile.OpenRead(filepath))
{
var data = archive.Entries.Single(e => e.FullName == "productdb.json");
return Task.FromResult(data.Open());
//using (var reader = new StreamReader(data.Open()))
//{
// var ms = new MemoryStream();
// data.Open().CopyTo(ms);
// ms.Seek(0, SeekOrigin.Begin);
// return Task.FromResult((Stream)ms);
//}
}
}
With the commented code you open the stream into a reader, don't use the reader, then open the stream again and copy over to the memory stream without closing the second opened stream.
It is the second opened stream that remains in memory, not the MemoryStream.
Refactor
public static async Task<Stream> GetDb() {
var filepath = Path.Combine("c:/users/tom/Downloads", "productdb.zip");
using (var archive = ZipFile.OpenRead(filepath)) {
var entry = archive.Entries.Single(e => e.FullName == "productdb.json");
using (var stream = entry.Open()) {
var ms = new MemoryStream();
await stream.CopyToAsync(ms);
return ms;
}
}
}
There is a method that builds reports. It generates stream on server and then save it to a tmp file.
public virtual void Build(ReportType reportType, ReportParameters parameters)
{
Export = reportType.Id == MaterialReportIds.WarehouseBalanceDynamic;
var tempFileName = Path.GetTempFileName();
try {
ServiceManager<IMaterialsReportsDataService>.Invoke(service =>
{
using (var stream = service.BuildReport(reportType, parameters)) {
using (var fileStream = File.Create(tempFileName)) {
int buf;
while ((buf = stream.ReadByte()) >= 0) {
fileStream.WriteByte((byte)buf);
}
fileStream.Flush();
fileStream.Close();
stream.Close();
}
}
});
Report.LoadPrepared(tempFileName);
}
finally {
File.Delete(tempFileName);
}
}
On service :
public Stream BuildReport(ReportType reportType, ReportParameters parameters) {
IReport report = new ReportFactory(Assembly.GetExecutingAssembly()).CreateReport(reportType);
try {
report.Build(reportType, parameters);
MemoryStream stream = new MemoryStream();
(report.Object as Stream)?.CopyTo(stream);
stream.Seek(0, SeekOrigin.Begin);
return stream;
} finally {
(report?.Object as IDisposable)?.Dispose();
}
}
After that we use Report.LoadPrepared(path to a tmp file) and it works, but when I try to use Report.Load(path to a tmp file) it doesn't. Do anybody know why? The error says that file format is incorrect, but why Report.LoadPrepared() works?
Just guessing from the documentation FastReport provided here.
Load method accepts ".frx" files:
report.Load("report1.frx");
From the other hand LoadPrepared accepts ".fpx" files:
Report.LoadPrepared(this.Server.MapPath("~/App_Data/Prepared.fpx"));
i have trouble with the following two functions. Both have a indentical basic scheme but first one work, second one causes an exception at marked line("File is used by another process").
// this works
public static void EncryptFile(string FileName)
{
string ToEncrypt = null;
using(StreamReader sr = new StreamReader(FileName))
{
ToEncrypt = sr.ReadToEnd();
}
using(StreamWriter sw = new StreamWriter(FileName, false))
{
string Encrypted = Encrypt(ToEncrypt, true);
sw.Write(Encrypted);
}
}
// this works not - see commented lin
public static void DecryptFile(string FileName)
{
string ToDecrypt = null;
using (StreamReader sr = new StreamReader(FileName))
{
ToDecrypt = sr.ReadToEnd();
}
// here comes the exception
using (StreamWriter sw = new StreamWriter(FileName, false))
{
string Decrypted = Decrypt(ToDecrypt, true);
sw.Write(Decrypted);
}
}
I have tried with an additional Close() after read and write, but this works not too.
I hope, somebody can help.
Thanks
Torsten
Is the function called from multiple threads? If yes you may want to declare a static object on class level and place a lock statement around the entire body of that method. Like this:
private static Object syncObject = new Object()
// this works not - see commented lin
public static void DecryptFile(string FileName)
{
lock(syncObject)
{
string ToDecrypt = null;
using (StreamReader sr = new StreamReader(FileName))
{
ToDecrypt = sr.ReadToEnd();
}
// here comes the exception
using (StreamWriter sw = new StreamWriter(FileName, false))
{
string Decrypted = Decrypt(ToDecrypt, true);
sw.Write(Decrypted);
}
}
}
Also could you, just for fun, comment the StreamReader statement and try to run the method again? If it still doesn't work, check if you've that file open in a texteditor or something alike by using ProcessExplorer or something similiar.
edit
could you comment the StreamReader part? So that it looks like this:
public static void DecryptFile(string FileName)
{
//string ToDecrypt = null;
//using (StreamReader sr = new StreamReader(FileName))
//{
// ToDecrypt = sr.ReadToEnd();
//}
// here comes the exception
using (StreamWriter sw = new StreamWriter(FileName, false))
{
string Decrypted = Decrypt(ToDecrypt, true);
sw.Write(Decrypted);
}
}
also could you try to open an exclusive FileStream on that file before the StreamReader and once after the StreamReader but before the StreamWriter? http://msdn.microsoft.com/de-de/library/tyhc0kft%28v=vs.110%29.aspx
Also could you try and use another file for that method?