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Can multiple zip file entries be active using ZipOutputStream class?

I am trying to use DotNetZip open source library for creating large zip files.
I need to be able to write to each stream writer part of the data row content (see the code below) of the data table. Other limitation I have is that I can't do this in memory due to the contents being large (several giga bytes each entry).
The problem I have is that despite writing to each stream separately, the output is all written to the last entry only. The first entry contains blank. Does anybody have any idea on how to fix this issue?
static void Main(string fileName)
{
var dt = CreateDataTable();
var streamWriters = new StreamWriter[2];
using (var zipOutputStream = new ZipOutputStream(File.Create(fileName)))
{
for (var i = 0; i < 2; i++)
{
var entryName = "file" + i + ".txt";
zipOutputStream.PutNextEntry(entryName);
streamWriters[i] = new StreamWriter(zipOutputStream, Encoding.UTF8);
}
WriteContents(streamWriters[0], streamWriters[1], dt);
zipOutputStream.Close();
}
}
private DataTable CreateDataTable()
{
var dt = new DataTable();
dt.Columns.AddRange(new DataColumn[] { new DataColumn("col1"), new DataColumn("col2"), new DataColumn("col3"), new DataColumn("col4") });
for (int i = 0; i < 100000; i++)
{
var row = dt.NewRow();
for (int j = 0; j < 4; j++)
{
row[j] = j * 1;
}
dt.Rows.Add(row);
}
return dt;
}
private void WriteContents(StreamWriter writer1, StreamWriter writer2, DataTable dt)
{
foreach (DataRow dataRow in dt.Rows)
{
writer1.WriteLine(dataRow[0] + ", " + dataRow[1]);
writer2.WriteLine(dataRow[2] + ", " + dataRow[3]);
}
}
Expected Results:
Both file0.txt and file1.txt need to written.
Actual results:
Only file1.txt file is written all content. file0.txt is blank.

It seems to be the expected behaviour according to the docs
If you don't call Write() between two calls to PutNextEntry(), the first entry is inserted into the zip file as a file of zero size. This may be what you want.
So to me it seems that it is not possible to do what you want through the current API.
Also, as zip file is a continuous sequence of zip entries, it is probably physically impossible to create entries in parallel, as you would have to know the size of each entry before starting a new one.
Perhaps you could just create separate archives and then combine them (if I am not mistaken there was a simple API to do that)

create lines with strings for each blank line until it reaches line 100

I'm new to C# i need help on reading a file that currently has 7 lines of text but I need it to write "Line PlaceHolder" after those 7 lines until it reaches line 100 in the text file. This is what i have so far and i know it's my failed attempt: EDIT: It's good but only issue is an exception is throw that a process is already using the text file, how do I solve this to read/write that file at the same time??
public void ReadFile()
{
if (File.Exists(AccountsFile))
{
using (StreamReader Reader = new StreamReader(AccountsFile))
using (StreamWriter Writer = new StreamWriter((AccountsFile)))
{
for (int i = 0; i < 100; i++)
{
string line;
if ((line = Reader.ReadLine()) == null)
{
Writer.WriteLine("Line Placeholder");
}
}
}
}
else
{
File.Create(AccountsFile);
}
}

You could first read the file contents into an array using File.ReadAllLines, get the array .Length (representing the number of lines in the file), and subtract that number from 100 to see how many lines you need to write. If the number is greater than zero, then create a List<string> with that many empty lines and write those lines to the end of the file using File.AppendAllLines:
// See how many lines we need to add
var newLinesNeeded = 100 - File.ReadAllLines(AccountsFile).Length;
// Add them if needed
if (newLinesNeeded > 0)
{
// Create a list of empty lines
var blankLines = new List<string>();
for(int i = 0; i < newLinesNeeded; i++)
{
blankLines.Add("");
}
// Append them to our file
File.AppendAllLines(AccountsFile, blankLines);
}

Looks like you are just missing an else:
public void ReadFile()
{
if (File.Exists(AccountsFile))
{
using (StreamReader Reader = new StreamReader(AccountsFile))
using (StreamWriter Writer = new StreamWriter((AccountsFile)))
{
for (int i = 0; i < 100; i++)
{
string line;
if ((line = Reader.ReadLine()) == null)
{
Writer.WriteLine("Line Placeholder");
}
else
Writer.WriteLine(line);
}
}
}
else
{
File.Create(AccountsFile);
}
}

this may work if you do not mind opening the file as Read/Write
using (FileStream fileStream = File.Open(AccountsFile, FileMode.OpenOrCreate, FileAccess.ReadWrite))
{
var streamWriter = new StreamWriter(fileStream);
var streamReader = new StreamReader(fileStream);
var i = 0;
// read and count the lines
while (streamReader.ReadLine() != null){
i++;
}
// if any more lines are needed write them
while (i++ < 100)
{
streamWriter.WriteLine("Line Placeholder");
}
streamWriter.Flush();
}

Output not correctly being written to CSV

So I am having an issue with my output being written to a CSV file. The output to this code is in the correct format when being written to the CSV file but it is only entering a single row in the file. There should be much more. Around 150 lines. Current out put is:
(859.85 7N830127 185)
Which is correct, but there should be more of these. It seems like to me that it is only writing the first line of the parsed EDI file and then stopping. I need to find a way to make sure it writes all data that is being parsed can anyone help me?
static void Main(string[] args)
{
StreamReader sr = new StreamReader("edifile.txt");
string[] ediMapTemp = sr.ReadLine().Split('|');
List<string[]> ediMap = new List<string[]>();
List<object[]> outputMatrix = new List<object[]>();
foreach (var line in ediMapTemp)
{
ediMap.Add(line.Split('~'));
}
DetailNode node = new DetailNode(0, null, 0);
int hierarchicalDepth = 0;
int hierarchicalIdNumber;
int hierarchicalParentIdNumber;
int hierarchicalLevelCode;
int hierarchicalChildCode = 0;
for (int i = 0; i < ediMap.Count; i++)
{
string segmentHeader = ediMap[i][0];
if (segmentHeader == "HL")
{
hierarchicalIdNumber = Convert.ToInt32(ediMap[i][1]);
hierarchicalParentIdNumber = Convert.ToInt32(ediMap[i][2]);
hierarchicalLevelCode = Convert.ToInt32(ediMap[i][3]);
hierarchicalChildCode = Convert.ToInt32(ediMap[i][4]);
List<string[]> levelDetails = new List<string[]>();
for (int v = i + 1; v < ediMap.Count; v++)
{
if (ediMap[v][0] == "HL") break;
levelDetails.Add(ediMap[v]);
}
DetailNode getNode = node.Find(node, hierarchicalParentIdNumber);
getNode.headList.Add(new DetailNode(hierarchicalIdNumber, levelDetails, getNode.depth + 1));
}
}
node.Traversal(new VID(), node);
foreach (var vid in VIDList.vidList)
using (StreamWriter writer = new StreamWriter("Import.csv"))
{
//probably a loop here
writer.WriteLine(String.Join(",", vid.totalCurrentCharges, vid.assetId, vid.componentName, vid.recurringCharge));
}
}

Quick Review, should the code be the following:
using (StreamWriter writer = new StreamWriter("Import.csv"))
{
//a loop here
foreach (var vid in VIDList.vidList)
{
writer.WriteLine(String.Join(",", vid.totalCurrentCharges, vid.assetId, vid.componentName, vid.recurringCharge));
}
}
You would open the file once and then loop thru your collection, writing each one.

It looks to me like you're re-opening the output file for each line you're trying to write, so you're overwriting the output file with a new file for each line. That would mean only the last entry remains in the file. Try moving this line
using (StreamWriter writer = new StreamWriter("Import.csv"))
Outside the foreach loop.

How do i change a specific line in a textfile

Im trying to read from a textfile into an array, change one element and then read array back into the file but not appending the original text. But it says the file is being used by another process. Any help is appreciated.
using (StreamReader readName = new StreamReader("fileA"))
{
using (StreamReader readColour = new StreamReader("fileB"))
{
var lineCount = File.ReadLines("fileB").Count();
string[] linesA = new string[lineCount];
string[] linesB = new string[lineCount];
for (int a = 0; a < linesA.Length; a++)
{
if (linesA[a] == UserVariables.userNameC)
{
linesB[a] = UserVariables.colourC.ToString();
}
}
}
}
try
{
using (StreamWriter colourWrite = new StreamWriter("fileB"))
{
for (int a = 0; a < linesB.Length; a++)
colourWrite.WriteLine(linesB[a], false);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString(), "Error");
}
}

You are trying to read fileB twice,
using (StreamReader readColour = new StreamReader("fileB")) <-- this opens
the file
here and
leaves it
open
{
var lineCount = File.ReadLines("fileB").Count(); <-- this tries to open it,
read it and close it..
but it can't because
you have it open
above..

This part opens fileB two times:
using (StreamReader readColour = new StreamReader("fileB"))
{
var lineCount = File.ReadLines("fileB").Count();

Try adding the line readColour.Close(); in between your read and write sections

How to write back to the CSV file

I am trying to write back to CSV file , How can I change this script to write back to CSV file,I am new to C#? Please help me
public void Main()
{
List<String> lines = new List<string>();
string line;
System.IO.StreamReader file = new System.IO.StreamReader("C:\\NewFolder\\Test.csv");
while ((line = file.ReadLine()) != null)
{
lines.Add(line);
}
lines.RemoveAll(l => l.Contains(",,,,,"));
using (System.IO.StreamWriter writer = new System.IO.StreamWriter("C:\\NewFolder\\Test.csv", false))
{
for (int i = 0; i < lines.Count; i++)
{
writer.WriteLine(lines[i]);
}
}
Dts.TaskResult = (int)ScriptResults.Success;
}

Simply this
//Convert your list to csv string
string toWrite = string.Join(",",lines );
File.WriteAllText(YourFilePath, toWrite);

You're using a StreamReader to read from the file. Use a StreamWriter to write back to it. This code should do it
using (System.IO.StreamWriter writer = new System.IO.StreamWriter("c:\\test.txt", false))
{
for (int i = 0; i < lines.Count; i++)
{
writer.WriteLine(lines[i]);
}
}
Note this assumes 2 things:
You've closed your reader
You're wanting to replace the original file
EDIT: Alternatively you can rewrite the whole thing as:
string fileName = "C:\\NewFolder\\Test.csv";
List<string> lines = System.IO.File.ReadAllLines(fileName).ToList();
lines.RemoveAll(l => l.Contains(",,,,,"));
System.IO.File.WriteAllLines(fileName, lines.ToArray());