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)
{
}
}
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.
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'm new to Streams and in the program i'm developing requires reading data from a hex file.
File=level.dat
The code im using:
FileStream fs;
private void Form1_Load(object sender, EventArgs e)
{
Main("PCWorld\\level.dat");
NbtTree nbtTree = new NbtTree();
Stream s = fs;
Stream destStream = new MemoryStream();
nbtTree.ReadFrom(s);
nbtTree.WriteTo(destStream);
}
void Main():
void Main(string filename)
{
// From MSDN Forums, slightly modified by me
try
{
string fileName = filename;
// Create random data to write to the file.
byte[] dataArray = new byte[100000];
new Random().NextBytes(dataArray);
using (FileStream
fileStream = new FileStream(fileName, FileMode.Create))
{
// Write the data to the file, byte by byte.
for (int i = 0; i < dataArray.Length; i++)
{
fileStream.WriteByte(dataArray[i]);
}
// Set the stream position to the beginning of the file.
fileStream.Seek(0, SeekOrigin.Begin);
// Read and verify the data.
for (int i = 0; i < fileStream.Length; i++)
{
if (dataArray[i] != fileStream.ReadByte())
{
MessageBox.Show("Failed to load " + fileName + " (MCPC.dll)\n\nReason: Failed to read bytes\nResult: Close();\nSoloution: Try again and/or tell DMP9 Software", "Error");
Close();
return;
}
fs = fileStream;
}
}
}
catch (OutOfMemoryException ex)
{
MessageBox.Show("Failed to load NBT++.PC.exe\n\nReason: Out of memory (System.OutOfMemoryException: " + ex.Message + ")\nResult: Close();\nSoloution: Your PC Does not have enough RAM to run NBT++", "Error");
Close();
}
}
My program has a reference of Substrate (https://code.google.com/p/substrate-minecraft/downloads/list) and that does most of the work, but its my code giving
the "Cannot access a closed file"
Any help?
Thanks...
Your problem is in:
Stream s = fs;
The fs filestream is closed in your Main method (using statement disposes the filestream). To fix this you should open a new filestream to read from the file:
Stream s = new FileStream("PCWorld\\level.dat", FileMode.Read);
When using
using (FileStream fileStream = new FileStream(fileName, FileMode.Create))
{...}
you are closing this filestream when you go out scope. So you have to re-open file to read
http://msdn.microsoft.com/en-us/library/yh598w02.aspx
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.
I'm trying to do custom serialization/deserialization of an object as well as compressing/decompressing the serialized data with DeflateStreams. I originally did this for more complex objects but cut it down to try and figure out the problem, however it just became more puzzling as it is still there. Here is the class to be serialized/deserialized:
[Serializable]
public class RandomObject : ISerializable
{
public String Name { get; set; }
public String SavePath { get; set; }
public RandomObject()
{
}
public RandomObject(String name, String savepath)
{
Name = name;
SavePath = savepath;
}
public RandomObject(SerializationInfo info, StreamingContext context)
: this(info.GetString("name"), info.GetString("savepath"))
{
}
[SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter = true)]
public void GetObjectData(SerializationInfo info, StreamingContext context)
{
info.AddValue("name", Name);
info.AddValue("savepath", SavePath);
}
}
And here is the code that is supposed to serialize it(which seems to work):
BinaryFormatter bf = new BinaryFormatter();
using (MemoryStream ms = new MemoryStream())
{
bf.Serialize(ms, profile);
using (DeflateStream ds = new DeflateStream(ms, CompressionMode.Compress))
{
try
{
using (FileStream fs = File.Create(path))
{
ds.Flush();
Miscellaneous.CopyStream(ds.BaseStream, fs);
fs.Flush();
fs.Close();
}
}
catch (IOException e)
{
MessageBox.Show(e.Message);
success = false;
}
ds.Close();
}
ms.Close();
}
And here is the deserialization:
RandomObject profile = null;
using (FileStream fs = File.OpenRead(path))
{
using (DeflateStream ds = new DeflateStream(fs, CompressionMode.Decompress))
{
BinaryFormatter bf = new BinaryFormatter();
ds.Flush();
using (MemoryStream ms = new MemoryStream())
{
Miscellaneous.CopyStream(ds.BaseStream, ms);
profile = bf.Deserialize(ms) as RandomObject;
profile.SavePath = path;
ms.Close();
}
ds.Close();
}
fs.Close();
}
Now, to the problem. Deserialization throws a SerializationException with the message {"No map for object '201326592'."} I have no idea how to troubleshoot or figure out what exactly is causing the problem. Very basic serialization works when I just run BinaryFormatter's Serialize and Deserialize methods on the same MemoryStream.
I tried removing the DeflateStream stuff from both methods, but it's still the same problem. When I look at the examples at MSDN and other places it looks like I'm doing it just right, and googling for the exception message doesn't give any meaningful results(or perhaps I'm just bad at searching).
PS. As you can see I use Miscellaneous.CopyStream(src, dest) which is a basic stream copier, as I can't get src.CopyTo(dest) to work at all, so any hints on that is welcome as well.
Below is a link to the whole VS2010 project if you would like to look at it more closely:
http://www.diredumplings.com/SerializationTesting.zip
UPDATE:
The_Smallest: I tried using the Compress method you posted on my serialization:
BinaryFormatter bf = new BinaryFormatter();
using (MemoryStream stream = new MemoryStream())
{
bf.Serialize(stream, profile);
byte[] array = Compress(stream);
using (MemoryStream ms = new MemoryStream(array))
{
using (FileStream fs = File.Create(path))
{
ms.WriteTo(fs);
fs.Flush();
}
}
}
However, it seems to give me the same problems that I had with srcStream.CopyTo(destStream) earlier, which is that it doesn't seem to get written to the stream. The result is a 0 kb file when I try to save it to disk. Any ideas?
Pieter: I removed the MemoryStream from the deserialization method and it seems have the same functionality as before. However I'm not sure how to implement the serialization the way you suggested. Is this what you had in mind?
BinaryFormatter bf = new BinaryFormatter();
using (FileStream fs = File.Create(path))
{
using (DeflateStream ds = new DeflateStream(fs, CompressionMode.Compress))
{
bf.Serialize(ds, profile);
fs.Flush();
ds.Close();
}
fs.Close();
}
Thanks to both of you!
I dowloaded you example and digged a little in there. See changes for your project below:
Replace LoadFromFile in Loader.cs
private static RandomObject LoadFromFile(string path)
{
try
{
var bf = new BinaryFormatter();
using (var fileStream = File.OpenRead(path))
using (var decompressed = new MemoryStream())
{
using (var deflateStream = new DeflateStream(fileStream, CompressionMode.Decompress))
deflateStream.CopyTo(decompressed);
decompressed.Seek(0, SeekOrigin.Begin);
var profile = (RandomObject)bf.Deserialize(decompressed);
profile.SavePath = path;
return profile;
}
}
catch (IOException e)
{
MessageBox.Show(e.Message);
return null;
}
}
Replace Save in Saver.cs as follows:
public static bool Save(RandomObject profile, String path)
{
try
{
var bf = new BinaryFormatter();
using (var uncompressed = new MemoryStream())
using (var fileStream = File.Create(path))
{
bf.Serialize(uncompressed, profile);
uncompressed.Seek(0, SeekOrigin.Begin);
using (var deflateStream = new DeflateStream(fileStream, CompressionMode.Compress))
uncompressed.CopyTo(deflateStream);
}
return true;
}
catch (IOException e)
{
MessageBox.Show(e.Message);
return false;
}
}
You should serialize into the DeflateStream, not the base (MemoryStream) stream.
For serializing: begin with the File.Create. Then around that stream, create the DeflateStream. Then to the DefaulteStream, serialize your objects.
For deserializing: do not create the MemoryStream and deserialize directly from the DeflateStream.
I believe there is no need for the added MemoryStream. If however you do have problems writing directly to/reading directly from the file streams, just change the serialize routine to write to the DeflateStream instead of the MemoryStream.
That should solve your issues.
There is error in streams logics, while compressing you should write to CompressStream, which writes to MemoryStream, after this you will have result in MemoryStream (not in CompressStream)
Here is example how to compress and decompress bytes
private static byte[] Compress(Stream stream)
{
using (var resultStream = new MemoryStream())
{
using (var gzipStream = new DeflateStream(resultStream, CompressionMode.Compress))
stream.CopyTo(gzipStream);
return resultStream.ToArray();
}
}
private static byte[] Decompress(byte[] bytes)
{
using (var readStream = new MemoryStream(bytes))
using (var resultStream = new MemoryStream())
{
using (var gzipStream = new DeflateStream(readStream, CompressionMode.Decompress))
gzipStream.CopyTo(resultStream);
return resultStream.ToArray();
}
}