Develop Reference

CSV appears to be corrupt on Double quotes in Headers - C#

I was trying to read CSV file in C#.
I have tried File.ReadAllLines(path).Select(a => a.Split(';')) way but the issue is when there is \n multiple line in a cell it is not working.
So I have tried below
using LumenWorks.Framework.IO.Csv;
var csvTable = new DataTable();
using (TextReader fileReader = File.OpenText(path))
using (var csvReader = new CsvReader(fileReader, false))
{
csvTable.Load(csvReader);
}
for (int i = 0; i < csvTable.Rows.Count; i++)
{
if (!(csvTable.Rows[i][0] is DBNull))
{
var row1= csvTable.Rows[i][0];
}
if (!(csvTable.Rows[i][1] is DBNull))
{
var row2= csvTable.Rows[i][1];
}
}
The issue is the above code throwing exception as
The CSV appears to be corrupt near record '0' field '5 at position '63'
This is because the header of CSV's having two double quote as below
"Header1",""Header2""
Is there a way that I can ignore double quotes and process the CSV's.
update
I have tried with TextFieldParser as below
public static void GetCSVData()
{
using (var parser = new TextFieldParser(path))
{
parser.HasFieldsEnclosedInQuotes = false;
parser.Delimiters = new[] { "," };
while (parser.PeekChars(1) != null)
{
string[] fields = parser.ReadFields();
foreach (var field in fields)
{
Console.Write(field + " ");
}
Console.WriteLine(Environment.NewLine);
}
}
}
The output:
Sample CSV data I have used:
Any help is appreciated.

Hope this works!
Please replace two double quotes as below from csv:
using (FileStream fs = new FileStream(Path, FileMode.Open, FileAccess.ReadWrite, FileShare.None))
{
StreamReader sr = new StreamReader(fs);
string contents = sr.ReadToEnd();
// replace "" with "
contents = contents.Replace("\"\"", "\"");
// go back to the beginning of the stream
fs.Seek(0, SeekOrigin.Begin);
// adjust the length to make sure all original
// contents is overritten
fs.SetLength(contents.Length);
StreamWriter sw = new StreamWriter(fs);
sw.Write(contents);
sw.Close();
}
Then use the same CSV helper
using LumenWorks.Framework.IO.Csv;
var csvTable = new DataTable();
using (TextReader fileReader = File.OpenText(path))
using (var csvReader = new CsvReader(fileReader, false))
{
csvTable.Load(csvReader);
}
Thanks.

How to read binary files until EOF in C#

I have a function to write some data into a binary file
private void writeToBinFile (List<MyClass> myObjList, string filePath)
{
FileStream fs = new FileStream(filePath, FileMode.Create);
BinaryWriter bw = new BinaryWriter(fs);
foreach (MyClass myObj in myObjList)
{
bw.Write(JsonConvert.SerializeObject(myObj));
}
bw.Close();
fs.Close();
}
I am looking something like
FileStream fs = new FileStream(filePath, FileMode.Create);
BinaryReader bw = new BinaryReader(fs);
while (!filePath.EOF)
{
List<MyClass> myObjList = br.Read(myFile);
}
anyone can help with this?
thanks in advance

JSON can be saved with no formatting (no new lines), so you can save 1 record per row of a file. Thus, my suggested solution is to ignore binary files and instead use a regular StreamWriter:
private void WriteToFile(List<MyClass> myObjList, string filePath)
{
using (StreamWriter sw = File.CreateText(filePath))
{
foreach (MyClass myObj in myObjList)
{
sw.Write(JsonConvert.SerializeObject(myObj, Newtonsoft.Json.Formatting.None));
}
}
}
private List<MyClass> ReadFromFile(string filePath)
{
List<MyClass> myObjList = new List<MyClass>();
using (StreamReader sr = File.OpenText(filePath))
{
string line = null;
while ((line = sr.ReadLine()) != null)
{
myObjList.Add(JsonConvert.DeserializeObject<MyClass>(line));
}
}
return myObjList;
}
If you really want to use the binary writer to save JSON, you could change it to be like this:
private void WriteToBinFile(List<MyClass> myObjList, string filePath)
{
using (FileStream fs = new FileStream(filePath, FileMode.Create))
using (BinaryWriter bw = new BinaryWriter(fs))
{
foreach (MyClass myObj in myObjList)
{
bw.Write(JsonConvert.SerializeObject(myObj));
}
}
}
private List<MyClass> ReadFromBinFile(string filePath)
{
List<MyClass> myObjList = new List<MyClass>();
using (FileStream fs = new FileStream(filePath, FileAccess.Read))
using (BinaryReader br = new BinaryReader(fs))
{
while (fs.Length != fs.Position) // This will throw an exception for non-seekable streams (stream.CanSeek == false), but filestreams are seekable so it's OK here
{
myObjList.Add(JsonConvert.DeserializeObject<MyClass>(br.ReadString()));
}
}
return myObjList;
}
Notes:
I've added using around your stream instantiations so that the files are properly closed when memory is freed
To check the stream is at the end, you have to compare Length to Position.

Create and write to a text file inmemory and convert to byte array in one go

How can I create a .csv file implicitly/automatically by using the correct method, add text to that file existing in memory and then convert to in memory data to a byte array?
string path = #"C:\test.txt";
File.WriteAllLines(path, GetLines());
byte[] bytes = System.IO.File.ReadAllBytes(path);
With that approach I create a file always (good), write into it (good) then close it (bad) then open the file again from a path and read it from the hard disc (bad)
How can I improve that?
UPDATE
One nearly good approach would be:
using (var fs = new FileStream(#"C:\test.csv", FileMode.Create, FileAccess.ReadWrite))
{
using (var memoryStream = new MemoryStream())
{
fs.CopyTo(memoryStream );
return memoryStream .ToArray();
}
}
but I am not able to write text into that filestream... just bytes...
UPDATE 2
using (var fs = File.Create(#"C:\temp\test.csv"))
{
using (var sw = new StreamWriter(fs, Encoding.Default))
{
using (var ms = new MemoryStream())
{
String message = "Message is the correct ääüö Pi(\u03a0), and Sigma (\u03a3).";
sw.Write(message);
sw.Flush();
fs.CopyTo(ms);
return ms.ToArray();
}
}
}
The string message is not persisted to the test.csv file. Anyone knows why?

Write text into Memory Stream.
byte[] bytes = null;
using (var ms = new MemoryStream())
{
using(TextWriter tw = new StreamWriter(ms)){
tw.Write("blabla");
tw.Flush();
ms.Position = 0;
bytes = ms.ToArray();
}
}
UPDATE
Use file stream Directly and write to File
using (var fs = new FileStream(#"C:\ed\test.csv", FileMode.Create, FileAccess.ReadWrite))
{
using (TextWriter tw = new StreamWriter(fs))
{
tw.Write("blabla");
tw.Flush();
}
}

You can get a byte array from a string using encoding:
Encoding.ASCII.GetBytes(aString);
Or
Encoding.UTF8.GetBytes(aString);
But I don't know why you would want a csv as bytes. You could load the entire file to a string, add to it and then save it:
string content;
using (var reader = new StreamReader(filename))
{
content = reader.ReadToEnd();
}
content += "x,y,z";
using (var writer = new StreamWriter(filename))
{
writer.Write(content);
}
Update: Create a csv in memory and pass back as bytes:
var stringBuilder = new StringBuilder();
foreach(var line in GetLines())
{
stringBuilder.AppendLine(line);
}
return Encoding.ASCII.GetBytes(stringBuilder.ToString());

file I/O in xna windows phone.... reading and writing text data

i wants to increment the score of player and check the highscore, so that i am storing score in text file.i am trying below code but it is throwing exception.
Exception : Value does not fall within the expected range.
public void storage()
{
var appstorage = IsolatedStorageFile.GetUserStoreForApplication();
String filename = "store.txt";
using (var file = appstorage.OpenFile(filename, FileMode.OpenOrCreate,FileAccess.ReadWrite))
{
using (var writer = new StreamWriter(file))
{
writer.Write(score);
}
using(var reader=new StreamReader(file))
{
playerscore =reader.ReadLine();
}
}
}

I am really not sure about windows phone support but in windows I would do it something like this
using (var file = File.Open(filename, FileMode.OpenOrCreate, FileAccess.ReadWrite))
{
using (var writer = new BinaryWriter(file))
{
writer.Write(score);
}
using (var reader = new BinaryReader(file))
{
playerscore = reader.ReadInt32();
}
}
Of course if you can only read an write text this would be the solution
using (var file = File.Open(filename, FileMode.OpenOrCreate,` FileAccess.ReadWrite))
{
using (var writer = new StreamWriter(file))
{
writer.WriteLine(score.ToString());
}
using (var reader = new StreamReader(file))
{
playerscore = int.Parse(reader.ReadLine());
}
}

C# Comparing two files and exporting matching lines based on delimiter

Here’s the scenario.
I have a text file(alpha), single column, with a bunch of items.
My 2nd file is a csv(delta) with 4 columns.
I have to have the alpha compare again the delta and create a new file (omega) in which anything that alpha matched delta, it would export only the first two columns from delta into a new .txt file.
Example:
(Alpha)
BeginID
(delta):
BeginID,Muchmore,Info,Exists
(Omega):
BeginID,Muchmore
This document will probably have 10k lines it in. Thanks for the help!

Here's a rough cut way of doing the task you need:
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
string alphaFilePath = #"C:\Documents and Settings\Jason\My Documents\Visual Studio 2008\Projects\Compte Two Files\Compte Two Files\ExternalFiles\Alpha.txt";
List<string> alphaFileContent = new List<string>();
using (FileStream fs = new FileStream(alphaFilePath, FileMode.Open))
using(StreamReader rdr = new StreamReader(fs))
{
while(!rdr.EndOfStream)
{
alphaFileContent.Add(rdr.ReadLine());
}
}
string betaFilePath = #"C:\Beta.csv";
StringBuilder sb = new StringBuilder();
using (FileStream fs = new FileStream(betaFilePath, FileMode.Open))
using (StreamReader rdr = new StreamReader(fs))
{
while(! rdr.EndOfStream)
{
string[] betaFileLine = rdr.ReadLine().Split(Convert.ToChar(","));
if (alphaFileContent.Contains(betaFileLine[0]))
{
sb.AppendLine(String.Format("{0}, {1}", betaFileLine[0], betaFileLine[1]));
}
}
}
using (FileStream fs = new FileStream(#"C:\Omega.txt", FileMode.Create))
using (StreamWriter writer = new StreamWriter(fs))
{
writer.Write(sb.ToString());
}
Console.WriteLine(sb.ToString());
}
}
}
Basically it reads a txt file, puts the contents in a list. Then it reads a csv file (assuming no columns) and matches the values to create a StringBuilder. In your code, substitute the StringBuilder with creating a new txt file.
EDIT: If you wish to have the code run in a button click, then put it in the button click handler (or a new routine and call that):
public void ButtonClick (Object sender, EventArgs e)
{
string alphaFilePath = #"C:\Documents and Settings\Jason\My Documents\Visual Studio 2008\Projects\Compte Two Files\Compte Two Files\ExternalFiles\Alpha.txt";
List<string> alphaFileContent = new List<string>();
using (FileStream fs = new FileStream(alphaFilePath, FileMode.Open))
using(StreamReader rdr = new StreamReader(fs))
{
while(!rdr.EndOfStream)
{
alphaFileContent.Add(rdr.ReadLine());
}
}
string betaFilePath = #"C:\Beta.csv";
StringBuilder sb = new StringBuilder();
using (FileStream fs = new FileStream(betaFilePath, FileMode.Open))
using (StreamReader rdr = new StreamReader(fs))
{
while(! rdr.EndOfStream)
{
string[] betaFileLine = rdr.ReadLine().Split(Convert.ToChar(","));
if (alphaFileContent.Contains(betaFileLine[0]))
{
sb.AppendLine(String.Format("{0}, {1}", betaFileLine[0], betaFileLine[1]));
}
}
}
using (FileStream fs = new FileStream(#"C:\Omega.txt", FileMode.Create))
using (StreamWriter writer = new StreamWriter(fs))
{
writer.Write(sb.ToString());
}
}

I'd probably load alpha into a collection then open delta for read, while not EOF readline into a string, split, if collection.contains column 0 then write to omega.
Done...