Develop Reference

StreamWriter: Starting and ending on a specific line number

I would like to ask some tips and help on a reading/writing part of my C#.
Situation:
I have to read a CSV file; - OK
If the CSV file name starts with "Load_", I want to write on another CSV the data from line 2 to the last one;
If the CSV file name starts with "RO_", I want to write on 2 different CSVs, 1 with the line 1 to 4 and the other 4 to the last one;
What I have so far is:
public static void ProcessFile(string[] ProcessFile)
{
// Keeps track of your current position within a record
int wCurrLine = 0;
// Number of rows in the file that constitute a record
const int LINES_PER_ROW = 1;
int ctr = 0;
foreach (string filename in ProcessFile)
{
var sbText = new System.Text.StringBuilder(100000);
int stop_line = 0;
int start_line = 0;
// Used for the output name of the file
var dir = Path.GetDirectoryName(filename);
var fileName = Path.GetFileNameWithoutExtension(filename);
var ext = Path.GetExtension(filename);
var folderbefore = Path.GetFullPath(Path.Combine(dir, #"..\"));
var lineCount = File.ReadAllLines(#filename).Length;
string outputname = folderbefore + "output\\" + fileName;
using (StreamReader Reader = new StreamReader(#filename))
{
if (filename.Contains("RO_"))
{
start_line = 1;
stop_line = 5;
}
else
{
start_line = 2;
stop_line = lineCount;
}
ctr = 0;
while (!Reader.EndOfStream && ctr < stop_line)
{
// Add the text
sbText.Append(Reader.ReadLine());
// Increment our current record row counter
wCurrLine++;
// If we have read all of the rows for this record
if (wCurrLine == LINES_PER_ROW)
{
// Add a line to our buffer
sbText.AppendLine();
// And reset our record row count
wCurrLine = 0;
}
ctr++;
} // end of the while
}
int total_lenght = sbText.Length
// When all of the data has been loaded, write it to the text box in one fell swoop
using (StreamWriter Writer = new StreamWriter(dir + "\\" + "output\\" + fileName + "_out" + ext))
{
Writer.Write.(sbText.);
}
} // end of the foreach
} // end of ProcessFile
I was thinking about using the IF/ELSE: "using (StreamWriter Writer = new StreamWriter(dir + "\" + "output\" + fileName + "_out" + ext))" part. However, I am not sure how to pass, to StreamWriter, to only write from/to a specific line number.
Any Help is welcome! If I am missing some information, please, let me know (I am pretty new on stackoverflow).
Thank you.

Code is way too complicated
using System.Collections.ObjectModel;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
namespace ConsoleApplication57
{
class Program
{
static void Main(string[] args)
{
}
public static void ProcessFile(string[] ProcessFile)
{
foreach (string filename in ProcessFile)
{
// Used for the output name of the file
var dir = Path.GetDirectoryName(filename);
var fileName = Path.GetFileNameWithoutExtension(filename);
var ext = Path.GetExtension(filename);
var folderbefore = Path.GetFullPath(Path.Combine(dir, #"..\"));
var lineCount = File.ReadAllLines(#filename).Length;
string outputname = folderbefore + "output\\" + fileName;
using (StreamWriter Writer = new StreamWriter(dir + "\\" + "output\\" + fileName + "_out" + ext))
{
int rowCount = 0;
using (StreamReader Reader = new StreamReader(#filename))
{
rowCount++;
string inputLine = "";
while ((inputLine = Reader.ReadLine()) != null)
{
if (filename.Contains("RO_"))
{
if (rowCount <= 4)
{
Writer.WriteLine(inputLine);
}
if (rowCount == 4) break;
}
else
{
if (rowCount >= 2)
{
Writer.WriteLine(inputLine);
}
}
} // end of the while
Writer.Flush();
}
}
} // end of the foreach
} // end of ProcessFile
}
}

You can use LINQ to Take and Skip lines.
public abstract class CsvProcessor
{
private readonly IEnumerable<string> processFiles;
public CsvProcessor(IEnumerable<string> processFiles)
{
this.processFiles = processFiles;
}
protected virtual IEnumerable<string> GetAllLinesFromFile(string fileName)
{
using(var stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read))
using(var reader = new StreamReader(stream))
{
var line = String.Empty;
while((line = reader.ReadLine()) != null)
{
yield return line;
}
}
}
protected virtual void ProcessFiles()
{
var sb1 = new StringBuilder();
var sb2 = new StringBuilder();
foreach(var file in this.processFiles)
{
var fileName = Path.GetFileNameWithoutExtension(file);
var lines = GetAllLinesFromFile(file);
if(fileName.StartsWith("RO_", StringComparison.InvariantCultureIgnoreCase))
{
sb1.AppendLine(lines.Take(4)); //take only the first four lines
sb2.AppendLine(lines.Skip(4).TakeWhile(s => !String.IsNullOrEmpty(s))); //skip the first four lines, take everything else
}
else if(fileName.StartsWith("Load_", StringComparison.InvariantCultureIgnoreCase)
{
sb2.AppendLine(lines.Skip(1).TakeWhile(s => !String.IsNullOrEmpty(s)));
}
}
// now write your StringBuilder objects to file...
}
protected virtual void WriteFile(StringBuilder sb1, StringBuilder sb2)
{
// ... etc..
}
}

Can I programatically copy my html selection

I have a html document that after being parsed contains only formatted text.I was wondering if it is possible to get its text like I would do if I was mouse-selecting it + copy + paste in new Text Document?
I know that this is possible in Microsoft.Office.Interop where I have .ActiveSelection property that selects the content of the open Word.
I need to find a way to load the html somehowe(maybe in a browser object) and then copy all of its content and assign it to a string.
var doc = new HtmlAgilityPack.HtmlDocument();
var documetText = File.ReadAllText(myhtmlfile.html, Encoding.GetEncoding(1251));
documetText = this.PerformSomeChangesOverDocument(documetText);
doc.LoadHtml(documetText);
var stringWriter = new StringWriter();
AgilityPackEntities.AgilityPack.ConvertTo(doc.DocumentNode, stringWriter);
stringWriter.Flush();
var titleNode = doc.DocumentNode.SelectNodes("//title");
if (titleNode != null)
{
var titleToBeRemoved = titleNode[0].InnerText;
document.DocumentContent = stringWriter.ToString().Replace(titleToBeRemoved, string.Empty);
}
else
{
document.DocumentContent = stringWriter.ToString();
}
and then I return the document object.The problem is that the string is not always formatted as I want it to be

You should be able to just use StreamReader and as you read each line just write it out using StreamWriter
Something like this will readuntil the end of your file and save it to a new one. If you need to do extra logic in the file I have a comment inserted to let you know where to do all that.
private void button4_Click(object sender, EventArgs e)
{
System.IO.StreamWriter writer = new System.IO.StreamWriter("C:\\XXX\\XXX\\XXX\\test2.html");
String line;
using (System.IO.StreamReader reader = new System.IO.StreamReader("C:\\XXX\\XXX\\XXX\\test.html"))
{
//Do until the end
while ((line = reader.ReadLine()) != null) {
//You can insert extra logic here if you need to omit lines or change them
writer.WriteLine(line);
}
//All done, close the reader
reader.Close();
}
//Flush and close the writer
writer.Flush();
writer.Close();
}
You can also save it to a string then just do whatever you want to with it. You can use new lines to keep the same format.
EDIT The below will tke into account your tags
private void button4_Click(object sender, EventArgs e)
{
String line;
String filetext = null;
int count = 0;
using (System.IO.StreamReader reader = new System.IO.StreamReader("C:\\XXXX\\XXXX\\XXXX\\test.html"))
{
while ((line = reader.ReadLine()) != null) {
if (count == 0) {
//No newline since its start
if (line.StartsWith("<")) {
//skip this it is formatted stuff
}
else {
filetext = filetext + line;
}
}
else {
if (line.StartsWith("<"))
{
//skip this it is formatted stuff
}
else
{
filetext = filetext + "\n" + line;
}
}
count++;
}
Trace.WriteLine(filetext);
reader.Close();
}
}

Add a line in a txt file

I have a txt file with data such as the following:
:10FF800000040B4E00040B4E00047D1400047D148D
:10FF900000040B4E0004CF6200040B4E00040B4E15
:10FFA00000040B4E00040B4E00040B4E00040B4EDD
:10FFB00000047D1400047D1400047D1400047D14ED
:10FFC00000040B4E000000000000000000000000D4
:10FFD0000000000000040B4E0000000000000000C4
:10FFE0000000000000000000000000000000000011
:10FFF0000000000000000000060000000000BFF844
:020000020000FC
:020000040014E6
:043FF0005AC8A58C7A
:00000001FF
what I want to do with my C# program is to add a line after or before a specific line, lets say add the line:
:020000098723060
before this line:
:020000020000FC
I have tried using the File.ReadLines("file.txt").Last(); but that just gives me the last one, what if i want the third or fourth? also, is there any way to identify the ":" in the file?

The simplest way - if you're happy to read the whole file into memory - would be just:
public void InsertLineBefore(string file, string lineToFind, string lineToInsert)
{
List<string> lines = File.ReadLines(file).ToList();
int index = lines.IndexOf(lineToFind);
// TODO: Validation (if index is -1, we couldn't find it)
lines.Insert(index, lineToInsert);
File.WriteAllLines(file, lines);
}
public void InsertLineAfter(string file, string lineToFind, string lineToInsert)
{
List<string> lines = File.ReadLines(file).ToList();
int index = lines.IndexOf(lineToFind);
// TODO: Validation (if index is -1, we couldn't find it)
lines.Insert(index + 1, lineToInsert);
File.WriteAllLines(file, lines);
}
There are significantly more efficient ways of doing this, but this approach is really simple.

A brute force approach
string[] lines = File.ReadAllLines("file.txt");
using(StreamWrite sw = new StreamWriter("file.txt"))
{
foreach(string line in lines)
{
if(line == ":020000020000FC")
sw.WriteLine(":020000098723060");
sw.WriteLine(line);
}
}

I would say it is better to read and write line by line, especially if the target file tend to be of large size:
using (StreamReader r = new StreamReader("Test.txt"))
{
using (StreamWriter w = new StreamWriter("TestOut.txt"))
{
while (!r.EndOfStream)
{
string line = r.ReadLine();
w.WriteLine(line);
if (line == ":020000020000FC")
w.WriteLine(":020000098723060");
}
w.Close();
r.Close();
}
}

Not sure if you're trying to avoid reading the entire file in due to size, etc...but can't you just read the file and then replace...e.g.
var text = readFile(somePath);
writeFile( text.replace(":020000020000FC\n",":020000098723060\n:020000020000FC\n") , somePath);

Here is a solution, though it may not be the best, it does work:
public void AddTextToFile(string filePath, int lineNumber, string txt) //zero based lineNumber
{
Collection<string> newLines = new Collection<string>(File.ReadAllLines(filePath).ToList());
if (lineNumber < newLines.Count)
newLines.Insert(lineNumber, txt);
else
newLines.Add(txt);
using (StreamWriter writer = new StreamWriter(filePath, false))
{
foreach (string s in newLines)
writer.WriteLine(s);
}
}
And to answer your question about determining if ":" exists in a string, the answer is yes, in the example above, you could check if the line contains it by...
if(newLines[idx].Contains(':'))
//do something

The ":" character doesn't really help the implementation, the lines are all newline-delimited already.
Here's an attempt at a method that doesn't load it all to memory or output to a different file.
Never cross the streams.
static Int32 GetCharPos(StreamReader s)
{
var ia = BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField;
Int32 charpos = (Int32)s.GetType().InvokeMember("charPos", ia, null, s, null);
Int32 charlen = (Int32)s.GetType().InvokeMember("charLen", ia, null, s, null);
return (Int32)s.BaseStream.Position - charlen + charpos;
}
static void Appsert(string data, string precedingEntry = null)
{
if (precedingEntry == null)
{
using (var filestream = new FileStream(dataPath, FileMode.Append))
using (var tw = new StreamWriter(filestream))
{
tw.WriteLine(data);
return;
}
}
int seekPos = -1;
using (var readstream = new FileStream(dataPath,
FileMode.Open, FileAccess.Read, FileShare.Write))
using (var writestream = new FileStream(dataPath,
FileMode.Open, FileAccess.Write, FileShare.Read))
using (var tr = new StreamReader(readstream))
{
while (seekPos == -1)
{
var line = tr.ReadLine();
if (line == precedingEntry)
seekPos = GetCharPos(tr);
else if (tr.EndOfStream)
seekPos = (int)readstream.Length;
}
writestream.Seek(seekPos, SeekOrigin.Begin);
readstream.Seek(seekPos, SeekOrigin.Begin);
int readLength = 0;
var readBuffer = new byte[4096];
var writeBuffer = new byte[4096];
var writeData = tr.CurrentEncoding.GetBytes(data + Environment.NewLine);
int writeLength = writeData.Length;
writeData.CopyTo(writeBuffer, 0);
while (true & writeLength > 0)
{
readLength = readstream.Read(readBuffer, 0, readBuffer.Length);
writestream.Write(writeBuffer, 0, writeLength);
var tmp = writeBuffer;
writeBuffer = readBuffer;
writeLength = readLength;
readBuffer = tmp;
}
}
}

C# - Writing a header to a log file using string builder

This should be an extremely easy fix, but for some reason I am missing something. All I am trying to do is get the String Builder function that I have to write the header, but for some reason it isnt currently.
When I try to change the if statement to !File.Exists(tempFileName), it does not run through my loop.
Any suggestions? Also, let me know if you need more info. Thanks in advance.
public static void Open(string tempFileName, string division,
int zipFiles, int conversions, int returnedFiles, int totalEmails)
{
StreamWriter dailyStats;
//This is where I am missing something
//I am passing in the original filename of a log, then adding "-Stats.log"
//so I can tell the difference between what is the new stats file, and the original log file
if (File.Exists(tempFileName))
{
dailyStats = new StreamWriter(tempFileName + "-Stats.log");
StringBuilder sb = new StringBuilder();
sb.Append("Division");
sb.Append("\t");
sb.Append("Zip Files");
sb.Append("\t");
sb.Append("Conversions");
sb.Append("\t");
sb.Append("Returned Files");
sb.Append("\t");
sb.Append("Total E-Mails");
sb.Append("\t");
}
else
{
dailyStats = File.AppendText(tempFileName + "-Stats.log");
}
if (writeLog)
{
//Use a string builder to assemble the content for performance reasons
StringBuilder s = new StringBuilder();
s.Append(division);
s.Append("\t");
s.Append(zipFiles);
s.Append("\t");
s.Append(conversions);
s.Append("\t");
s.Append(returnedFiles);
s.Append("\t");
s.Append(totalEmails);
s.Append("\t");
dailyStats.WriteLine(s.ToString());
}
dailyStats.Close();
}

Are you not missing code in the first block?:
dailyStats.WriteLine(sb.ToString());
Thus:
if (File.Exists(tempFileName))
{
dailyStats = new StreamWriter(tempFileName + "-Stats.log");
StringBuilder sb = new StringBuilder();
sb.Append("Division");
sb.Append("\t");
sb.Append("Zip Files");
sb.Append("\t");
sb.Append("Conversions");
sb.Append("\t");
sb.Append("Returned Files");
sb.Append("\t");
sb.Append("Total E-Mails");
sb.Append("\t");
// Add this ......
dailyStats.WriteLine(sb.ToString());
}

You can fix it like this
var sb = new StringBuilder();
string logFileName = tempFileName + "-Stats.log";
if (File.Exists(logFileName)) {
dailyStats = File.AppendText(logFileName);
} else {
dailyStats = new StreamWriter(logFileName);
// Write header
sb.Append("Division");
...
sb.AppendLine();
}
if (writeLog) {
sb.Append(division);
...
dailyStats.WriteLine(sb.ToString());
}
dailyStats.Close();
UPDATE
The code had different errors. Two StringBuilders were created, but only one was written to the file. The existence of the file was determined for a different file name than the actual file that was written to. And finally, the logic depending on the existence of the file was inverted. I rewrote and refactored the code completely, in order to make it more understandable and manageable
public static void Open(string tempFileName, string division,
int zipFiles, int conversions, int returnedFiles, int totalEmails)
{
if (!writeLog)
return;
using (StreamWriter dailyStats = OpenLogFile(tempFileName)) {
var sb = new StringBuilder();
sb.Append(division);
// ...
dailyStats.WriteLine(sb.ToString());
}
}
private static StreamWriter OpenLogFile(string tempFileName)
{
StreamWriter dailyStats;
string logFileName = tempFileName + "-Stats.log";
if (File.Exists(logFileName)) {
dailyStats = File.AppendText(logFileName);
} else {
dailyStats = new StreamWriter(logFileName);
WriteHeader(dailyStats);
}
return dailyStats;
}
private static void WriteHeader(StreamWriter dailyStats)
{
var sb = new StringBuilder();
sb.Append("Division");
// ...
dailyStats.WriteLine(sb.ToString());
}
Note: The using statement closes the file and releases the external resources automatically.

You're creating a second StringBuilder and not doing anything with it. You probably want to just define the StringBuilder at a higher level so that appending to it in either block all adds it to one SB which can be written out at the end.
The other option of course is to write out the contents of the StringBuilder used to write the header to dailyStats rather than just doing nothing with it after appending the strings.

Using StreamReader to check if a file contains a string

I have a string that is args[0].
Here is my code so far:
static void Main(string[] args)
{
string latestversion = args[0];
// create reader & open file
using (StreamReader sr = new StreamReader("C:\\Work\\list.txt"))
{
while (sr.Peek() >= 0)
{
// code here
}
}
}
I would like to check if my list.txt file contains args[0]. If it does, then I will create another process StreamWriter to write a string 1 or 0 into the file. How do I do this?

Are you expecting the file to be particularly big? If not, the simplest way of doing it would be to just read the whole thing:
using (StreamReader sr = new StreamReader("C:\\Work\\list.txt"))
{
string contents = sr.ReadToEnd();
if (contents.Contains(args[0]))
{
// ...
}
}
Or:
string contents = File.ReadAllText("C:\\Work\\list.txt");
if (contents.Contains(args[0]))
{
// ...
}
Alternatively, you could read it line by line:
foreach (string line in File.ReadLines("C:\\Work\\list.txt"))
{
if (line.Contains(args[0]))
{
// ...
// Break if you don't need to do anything else
}
}
Or even more LINQ-like:
if (File.ReadLines("C:\\Work\\list.txt").Any(line => line.Contains(args[0])))
{
...
}
Note that ReadLines is only available from .NET 4, but you could reasonably easily call TextReader.ReadLine in a loop yourself instead.

You should not add the ';' at the end of the using statement.
Code to work:
string latestversion = args[0];
using (StreamReader sr = new StreamReader("C:\\Work\\list.txt"))
using (StreamWriter sw = new StreamWriter("C:\\Work\\otherFile.txt"))
{
// loop by lines - for big files
string line = sr.ReadLine();
bool flag = false;
while (line != null)
{
if (line.IndexOf(latestversion) > -1)
{
flag = true;
break;
}
line = sr.ReadLine();
}
if (flag)
sw.Write("1");
else
sw.Write("0");
// other solution - for small files
var fileContents = sr.ReadToEnd();
{
if (fileContents.IndexOf(latestversion) > -1)
sw.Write("1");
else
sw.Write("0");
}
}

if ( System.IO.File.ReadAllText("C:\\Work\\list.txt").Contains( args[0] ) )
{
...
}

The accepted answer reads all file in memory which can be consuming.
Here's an alternative inspired by VMAtm answer
using (var sr = new StreamReader("c:\\path\\to\\file", true))
for (string line; (line = sr.ReadLine()) != null;) //read line by line
if (line.Contains("mystring"))
return true;