I'm having problems converting long into string.
What I'm doing is trying to save a DateTime.Now.Ticks property in isolatedStorage, then retrieve it afterwords. This is what I did to save it:
IsolatedStorageFile appStorage = IsolatedStorageFile.GetUserStoreForApplication();
using (var file = appStorage.CreateFile("appState"))
{
using (var sw = new StreamWriter(file))
{
sw.Write(DateTime.Now.Ticks);
}
}
When I retrieve the file, I do it like this:
if (appStorage.FileExists("appState"))
{
using (var file = appStorage.OpenFile("appState", FileMode.Open))
{
using (StreamReader sr = new StreamReader(file))
{
string s = sr.ReadToEnd();
}
}
appStorage.DeleteFile("appState");
}
Until here I have no problem, but when I try to convert the string I retrieved, the compiler throws a FormatExeption. This are the two ways I tried to do it with:
long time = long.Parse(s);
long time = (long)Convert.ToDouble(s);
So is there any other ways to so this?
EDIT:
The problem is not in the conversion but rather in the StreamWriter adding extra characters.
I suspect you are seeing some other data at the end. Something else may have written other data to the stream.
I think you should use StreamWriter.WriteLine() instead of StreamWriter.Write() to write the data and then call StreamReader.ReadLine() instead of StreamReader.ReadToEnd() to read it back in.
Related
Here is the code im using to write and read from text file.
StreamWriter sw1 = new StreamWriter("DataNames.txt");
sw1.WriteLine(textBox1.Text);
sw1.Close();
StreamWriter sw2 = new StreamWriter("DataNumbers.txt");
sw2.WriteLine(textBox2.Text);
sw2.Close();
FileInfo file1 = new FileInfo("DataNames.txt");
StreamReader sr1 = file1.OpenText();
while (!sr1.EndOfStream)
{
listBox1.Items.Add(sr1.ReadLine());
}
FileInfo file2 = new FileInfo("DataNumbers.txt");
StreamReader sr2 = file2.OpenText();
while (!sr2.EndOfStream)
{
listBox2.Items.Add(sr2.ReadLine());
}
The thing is that when I click my button to save data from my textboxes to my text files an error appears that says "The process cannot access the file 'C:\xxxx\xxxxxx\xxxxx\xxxx\xxxxx\xxxxx.txt' because it is being used by another process."
Can anyone tell me why I have this error and maybe help me fix it
Try added a using statment around your streams to make sure they are Disposed otherwise the file is still locked to the stream
Example:
//Write
using (StreamWriter sw1 = new StreamWriter("DataNames.txt"))
{
sw1.WriteLine(textBox1.Text);
}
using (StreamWriter sw2 = new StreamWriter("DataNumbers.txt"))
{
sw2.WriteLine(textBox2.Text);
}
// Read
foreach (var line in File.ReadAllLines("DataNames.txt"))
{
listBox1.Items.Add(line);
}
foreach (var line in File.ReadAllLines("DataNumbers.txt"))
{
listBox2.Items.Add(line);
}
It appears you do not close the file after you read it. After you call FileInfo.OpenText you get a StreamReader which has to be closed, either via Close method, or even better, with a using statement.
But there are already methods that do all that for you, have a look at File.WriteAllText,
File.AppendAllText and File.ReadAllLines methods.
You need to Close the StreamReader object once you do not need it any more. This should fix this issue.
I.e.
StreamReader sr1 = file1.OpenText();
try {
while (!sr1.EndOfStream)
{
listBox1.Items.Add(sr1.ReadLine());
}
}
finally {
sr1.Close();
}
FileInfo file2 = new FileInfo("DataNumbers.txt");
StreamReader sr2 = file2.OpenText();
try {
while (!sr2.EndOfStream)
{
listBox2.Items.Add(sr2.ReadLine());
}
}
finally {
sr2.Close();
}
You have opened files but not closed.
StreamReader sr1 = file1.OpenText();
StreamReader sr2 = file2.OpenText();
Your problem occurs, because you are not closing the stream readers.
A safer way of using external resources (the files in this case) is to embed their use in a using statement. The using statement automatically closes the resource at the end of the statement block or if the statement block if left in another way. This could be a return statement or an exception, for instance. It is guaranteed that the resource will be closed, even after an exception occurs.
You can apply the using statement on any object which implements the IDisposable interface.
// Writing to the files
using (var sw1 = new StreamWriter("DataNames.txt")) {
sw1.WriteLine(textBox1.Text);
}
using(var sw2 = new StreamWriter("DataNumbers.txt")) {
sw2.WriteLine(textBox2.Text);
}
// Reading from the files
FileInfo file1 = new FileInfo("DataNames.txt");
using (StreamReader sr1 = file1.OpenText()) {
while (!sr1.EndOfStream) {
listBox1.Items.Add(sr1.ReadLine());
}
}
FileInfo file2 = new FileInfo("DataNumbers.txt");
using (StreamReader sr2 = file2.OpenText()) {
while (!sr2.EndOfStream)
{
listBox2.Items.Add(sr2.ReadLine());
}
}
However, you can simplify the reading part like this
// Reading from the files
listBox1.Items.AddRange(File.ReadAllLines("DataNames.txt"));
listBox2.Items.AddRange(File.ReadAllLines("DataNumbers.txt"));
I've seen this behavior before - usually there's another process open that's blocking the file access. Do you have multiple development servers open in your taskbar? (Strange, yes, but I've seen it happen)
I am trying to use LINQtoCSV to parse out a CSV file into a list of objects and am receiving the error "Stream provided to read is either null, or does not support seek."
The error is happening at foreach(StockQuote sq in stockQuotesStream)
Below is the method that is throwing the error. The .CSV file is being downloaded from the internet and is never stored to disk (only stored to StreamReader).
public List<StockQuote> CreateStockQuotes(string symbol)
{
List<StockQuote> stockQuotes = new List<StockQuote>();
CsvFileDescription inputFileDescription = new CsvFileDescription
{
SeparatorChar = ',',
FirstLineHasColumnNames = false
};
CsvContext cc = new CsvContext();
IEnumerable<StockQuote> stockQuotesStream = cc.Read<StockQuote>(GetCsvData(symbol));
foreach (StockQuote sq in stockQuotesStream)
{
stockQuotes.Add(sq);
}
return stockQuotes;
}
The .CSV file is being downloaded from the internet and is never stored to disk (only stored to StreamReader).
Well presumably that's the problem. It's not quite clear what you mean by this, in that if you have wrapped a StreamReader around it, that's a pain in terms of the underlying stream - but you can't typically seek on a stream being downloaded from the net, and it sounds like the code you're using requires a seekable stream.
One simple option is to download the whole stream into a MemoryStream (use Stream.CopyTo if you're using .NET 4), then rewind the MemoryStream (set Position to 0) and pass that to the Read method.
Using a MemoryStream first and then a StreamReader was the answer, but I went about it a little differently than mentioned.
WebClient client = new WebClient();
using (MemoryStream download = new MemoryStream(client.DownloadData(url)))
{
using (StreamReader dataReader = new StreamReader(download, System.Text.Encoding.Default, true))
{
return dataReader;
}
}
It gives operation not permitted on IsolatedStorageFileStream error when I try to save the content of the file in the fileStream fs.
var appStorage = IsolatedStorageFile.GetUserStoreForApplication();
string[] fileList = appStorage.GetFileNames();
foreach (string fileName in fileList)
{
using (var file = appStorage.OpenFile(fileName, FileMode.Open))
{
if (fileName != "__ApplicationSettings")
{
var fs = new IsolatedStorageFileStream(fileName, FileMode.Open, FileAccess.Read, appStorage);
string abc = fs.ToString();
meTextBlock.Text = abc;
//MemoryStream ms = appStorage.OpenFile(fileName, FileMode.Open, FileAccess.Read);
clientUpload.UploadAsync(SkyDriveFolderId, fileName, fs);
}
}
}
Why did you add the inner using (var file = appStorage.OpenFile(fileName, FileMode.Open))?
Seems to me the problem is that you're opening a stream to read the file and then opening another, without closing the previous one!
If you remove that line (seems not to be doing anything there) it should work fine.
Oh, and the fs.ToString() will only get you the Type name, not the file content; to read the file, use a StreamReader with the fs.
This error consistently occurs when an isolated storage file is opened by one stream (or reader or else) and, is being accessed by another object while the first stream (or reader, or else) have not yet relinquished the file. Go through your code carefully in all places where you access isolated storage files and make sure you close each file before something else is accessing it. Pedro Lamas is correct for this particular case, I just wanted to provide some general feedback. If you search google for "Operation not permitted on IsolatedStorageFileStream error" questions and answers, you will see the trend. The error message could be more descriptive though.
Try this approach
using (var isf = IsolatedStorageFile.GetUserStoreForApplication())
{
if (IsolatedStorageFile.IsEnabled)
{
if (isf.FileExists(localFileName))
{
using (var isfs = new IsolatedStorageFileStream(localFileName, FileMode.Open, isf))
{
using (var sr = new StreamReader(isfs))
{
var data = sr.ReadToEnd();
if (data != null)
{
...
I use StreamReader to read my csv file.
The problem is : i need to read this file twice, and in second time then i use StreamReader
StreamReader.EndOfStream is true and reading not executed.
using (var csvReader = new StreamReader(file.InputStream))
{
string inputLine = "";
var values = new List<string>();
while ((inputLine = csvReader.ReadLine()) != null)...
Can enybody help
Try file.InputStream.Seek(0, SeekOrigin.Begin); before you open the second StreamReader to reset the Stream to the starting point.
A much better approach(if possible) would be to store the file contents in memory, and re-use it from there.
It appears that JSON.NET is writing invalid JSON, although I wouldn't be surprised if it was due to my misuse.
It appears that it is repeating the last few characters of JSON:
/* ... */ "Teaser":"\nfoo.\n","Title":"bar","ImageSrc":null,"Nid":44462,"Vid":17}]}4462,"Vid":17}]}
The repeating string is:
4462,"Vid":17}]}
I printed it out to the console, so I don't think this is a bug in Visual Studio's text visualizer.
The serialization code:
static IDictionary<int, ObservableCollection<Story>> _sectionStories;
private static void writeToFile()
{
IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForApplication();
using (IsolatedStorageFileStream stream = storage.OpenFile(STORIES_FILE, FileMode.OpenOrCreate))
{
using (StreamWriter writer = new StreamWriter(stream))
{
writer.Write(JsonConvert.SerializeObject(_sectionStories));
}
}
#if DEBUG
StreamReader reader = new StreamReader(storage.OpenFile(STORIES_FILE, FileMode.Open));
string contents = reader.ReadToEnd();
JObject data = JObject.Parse(contents);
string result = "";
foreach (char c in contents.Skip(contents.Length - 20))
{
result += c;
}
Debug.WriteLine(result);
// crashes here with ArgumentException
// perhaps because JSON is invalid?
var foo = JsonConvert.DeserializeObject<Dictionary<int, List<Story>>>(contents);
#endif
}
Am I doing something wrong here? Or is this a bug? Are there any known workarounds?
Curiously, JObject.Parse() doesn't throw any errors.
I'm building a Silverlight app for Windows Phone 7.
When writing the file you specify
FileMode.OpenOrCreate
If the file exists and is 16 bytes longer than the data you intend to write to it (from an older version of your data that just happens to end with the exact same data) then that data will still be present when you're done writing your new data.
Solution:
FileMode.Create
From:
http://msdn.microsoft.com/en-us/library/system.io.filemode.aspx
FileMode.Create: Specifies that the operating system should create a new file. If the file already exists, it will be overwritten