I have the following class which writes new line to a text file.
using System;
using System.Text;
using System.IO;
namespace TextStreamer
{
class TextWriter
{
private string _FilePath;
private string _TextToAdd;
// Constructor will assign file Path variable and check if file is valid
public TextWriter(string filePath)
{
this._FilePath = filePath;
ValidateFile();
}
// Validate if the text file exist
private void ValidateFile()
{
// If file does not exist show error message
// and create new text file
if(!File.Exists(_FilePath))
{
Console.WriteLine("File not found");
File.Create(_FilePath);
Console.WriteLine("Created new file {0}", _FilePath);
}
}
// Write new line to the text file
public void WriteNewLine(string text)
{
this._TextToAdd = text + Environment.NewLine;
File.AppendAllText(_FilePath, _TextToAdd);
}
}
}
Right now if the file does not exist it will write a message to the console and then it will create the text file, but what if i used say WPF application, in this case i prefer showing a message box with the same message, how can i achieve that.
I tried throwing exception FileNotFoundException but that just crashes the program and exit.
A simple way to achieve this is by using a public variable to change the option to console log or show message.
Add the namespace for the generic message box:
using System.Windows;
And add a public variable in your class that will let you programmatically change the logging method, such as:
public bool UseMsgBox = false;
You could improve this by using things like using an int or enum to have more logging methods, though a bool is fine for only 2 options.
Add a logging method such as:
private void LogMsg(string msg)
{
if(UseNsgBox) MessageBox.Show(msg);
else Console.WriteLine(msg);
}
And replace your Console.WriteLine's with LogMsg instead.
Make sure to change the option when you create your class:
TextWriter textWriter = new TextWriter("SomeFile.txt");
textWriter.UseMsgBox = true; // or false
Actually, this might not work as you instantly call the LogMsg when your class is created, so perhaps add it as an initialization parameter as well:
public TextWriter(string filePath, bool useMsgBox = false)
{
UseMsgBox = useMsgBox;
// ...
}
I have a Test.cs file in C:\ This test file reads from an input file and writes the same to an output file.
Test.cs
public class Test
{
public static int Main(string[] args)
{
var reader = new StreamReader("in.txt");
string input = reader.ReadLine();
var writer = new StreamWriter("out.txt");
writer.WriteLine(input);
return 0;
}
}
Here it should be noted that the code only uses the filename and not the full file path, which means the file is expected to be in the directory where the program is running. And I have created the in.txt in C:\
Now, there is a c# code called Runner.cs in a solution in C:\Project\Runner.cs, that dynamically compiles the Test.cs code and runs it using reflection. Now, when the Test.cs runs, it expects the in.txt file to be in C:\Project\bin\Debug\in.txt , but it is actually present in C:\in.txt
So, my question is, is there a way to make the code to get the file from C:\in.txt and not from the bin directory without changing the path of the file in the Test.cs code file.
Edit: It is my bad that I forgot to mention why I am in need of this requirement.
The Test.cs file comes from over the wire. And I felt it will not be a good choice to edit this file and set the file path accordingly. I want to compile it and run it as it is.
I hope I am clear. If not, please feel free to ask for more information.
If it is as simple as you show in your code switching the CurrentDirectory works for this example:
var mainMembers = new CSharpCodeProvider()
.CreateCompiler()
.CompileAssemblyFromSource(
new CompilerParameters { GenerateInMemory = true }
, #"
using System;
using System.IO;
public class M {
public static int Main() {
Console.WriteLine(""CurDir = ""+ Environment.CurrentDirectory);
var reader = new StreamReader(""in.txt"");
string input = reader.ReadLine();
var writer = new StreamWriter(""out.txt"");
writer.WriteLine(input);
return 0;
}
}")
.CompiledAssembly
.GetType("M")
.GetMember("Main");
// inspect
Environment.CurrentDirectory.Dump("current");
// keep
var oldcd = Environment.CurrentDirectory;
// switch
Environment.CurrentDirectory = "c:\\temp";
// invoke external code
((MethodInfo) mainMembers[0]).Invoke(null,null);
// restore
Environment.CurrentDirectory = oldcd;
In a multi threaded scenario this becomes unreliable.
I found this answer https://stackoverflow.com/a/14336292/1537195 which gave a good way to detect password protection for DOC and XLS files.
//Flagged with password
if (bytes.Skip(0x20c).Take(1).ToArray()[0] == 0x2f) return true; //XLS 2003
if (bytes.Skip(0x214).Take(1).ToArray()[0] == 0x2f) return true; //XLS 2005
if (bytes.Skip(0x20B).Take(1).ToArray()[0] == 0x13) return true; //DOC 2005
However it does not seem to cover all XLS files and I am also looking for a way to detect PPT files in the same manner. Does anyway know which bytes to look at for these file types?
I saved a PowerPoint presentation as .ppt and .pptx with and without a password required for opening them, opened them in 7-Zip and came to the tentative conclusion that
.pptx files without a password always use a standard .zip file format
.ppt files are CompoundDocuments
.pptx files with a password also CompoundDocuments
All passworded CompoundDocuments contain an entry named *Encrypt*
To get this code running, you need to installed the NuGet package OpenMcdf. This is the first C# library that I could find for reading CompoundDocuments.
using OpenMcdf;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
namespace _22916194
{
//http://stackoverflow.com/questions/22916194/detecing-password-protected-ppt-and-xls-documents
class Program
{
static void Main(string[] args)
{
foreach (var file in args.Where(File.Exists))
{
switch (Path.GetExtension(file))
{
case ".ppt":
case ".pptx":
Console.WriteLine($"* {file} " + (HasPassword(file) ? "is " : "isn't ") + "passworded");
Console.WriteLine();
break;
default:
Console.WriteLine($" * Unknown file type: {file}");
break;
}
}
Console.ReadLine();
}
private static bool HasPassword(string file)
{
try
{
using (var compoundFile = new CompoundFile(file))
{
var entryNames = new List<string>();
compoundFile.RootStorage.VisitEntries(e => entryNames.Add(e.Name), false);
//As far as I can see, only passworded files contain an entry with a name containing Encrypt
foreach (var entryName in entryNames)
{
if (entryName.Contains("Encrypt"))
return true;
}
compoundFile.Close();
}
}
catch (CFFileFormatException) {
//This is probably a .zip file (=unprotected .pptx)
return false;
}
return false;
}
}
}
You should be able to extend this code to handle other Office formats. The conclusions at the top should hold true, except that you need to look for some other data in the CompoundDocument than a filename containing *Encrypt* (I had a quick look at .doc files and it didn't seem to work exactly the same).
I have not found yet a file-rename-function in .NET for C#, so I'm a bit confused how I would rename a file. I use the command prompt with Process.Start, but this isn't really professional and a black DOS window is popping up each time. Yes, I know there is something in the Visual Basic namespace, but this is not my intention to add the "visual-basic.dll" to my project.
I found some examples which "move" the file to rename it. It is a quite painful method and a shoddy workaround for things. Such footwork I can program myself.
Every language has renaming commands, so I am stunned that C# hasn't or I haven't found out yet. What is the right command?
For large files and to rename on CD, this code works, but your project will be partly converted into Visual Basic (as I understand it, maybe it is not so):
//Add the Microsoft.VisualBasic.MyServices reference and namespace in a project;
//For directories:
private static bool RenameDirectory(string DirPath, string NewName)
{
try
{
FileSystemProxy FileSystem = new Microsoft.VisualBasic.Devices.Computer().FileSystem;
FileSystem.RenameDirectory(DirPath, NewName);
FileSystem = null;
return true;
}
catch {
return false;
} //Just shut up the error generator of Visual Studio
}
//For files:
private static bool RenameFile(string FilePath, string NewName)
{
try
{
FileSystemProxy FileSystem = new Microsoft.VisualBasic.Devices.Computer().FileSystem;
FileSystem.RenameFile(FilePath, NewName);
FileSystem = null;
return true;
}
catch {
return false;
} //Just shut up the error generator of Visual Studio
}
A rename is just a move and vice versa, see the MSDN : File.Move
In the OS the operations are the same for all intents an purposes. That's why in explorer a move on the same partition is near instantaneous - just adjusts the file name and logical location. To Rename a file in the same directory you Move it to a new File Name in the same directory.
using System;
using System.IO;
class Test
{
public static void Main()
{
string path = #"c:\temp\MyTest.txt";
string path2 = #"c:\temp2\MyTest.txt";
try
{
if (!File.Exists(path))
{
// This statement ensures that the file is created,
// but the handle is not kept.
using (FileStream fs = File.Create(path)) {}
}
// Ensure that the target does not exist.
if (File.Exists(path2))
File.Delete(path2);
// Move the file.
File.Move(path, path2);
Console.WriteLine("{0} was moved/renamed to {1}.", path, path2);
// See if the original exists now.
if (File.Exists(path))
{
Console.WriteLine("The original file still exists, which is unexpected.");
}
else
{
Console.WriteLine("The original file no longer exists, which is expected.");
}
}
catch (Exception e)
{
Console.WriteLine("The process failed: {0}", e.ToString());
}
}
}
I am storing logs in an xml file...
In a traditional straight text format approach, you would typically just have a openFile... then writeLine method...
How is it possible to add a new entry into the xml document structure, like you would just with the text file approach?
use an XmlWriter.
example code:
public class Quote
{
public string symbol;
public double price;
public double change;
public int volume;
}
public void Run()
{
Quote q = new Quote
{
symbol = "fff",
price = 19.86,
change = 1.23,
volume = 190393,
};
WriteDocument(q);
}
public void WriteDocument(Quote q)
{
var settings = new System.Xml.XmlWriterSettings
{
OmitXmlDeclaration = true,
Indent= true
};
using (XmlWriter writer = XmlWriter.Create(Console.Out, settings))
{
writer.WriteStartElement("Stock");
writer.WriteAttributeString("Symbol", q.symbol);
writer.WriteElementString("Price", XmlConvert.ToString(q.price));
writer.WriteElementString("Change", XmlConvert.ToString(q.change));
writer.WriteElementString("Volume", XmlConvert.ToString(q.volume));
writer.WriteEndElement();
}
}
example output:
<Stock Symbol="fff">
<Price>19.86</Price>
<Change>1.23</Change>
<Volume>190393</Volume>
</Stock>
see
Writing with an XmlWriter
for more info.
One of the problems with writing a log file in XML format is that you can't just append lines to the end of the file, because the last line has to have a closing root element (for the XML to be valid)
This blog post by Filip De Vos demonstrates quite a good solution to this:
High Performance writing to XML Log files (edit: link now dead so removed)
Basically, you have two XML files linked together using an XML-include thing:
Header file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log [
<!ENTITY loglines SYSTEM "loglines.xml">
]>
<log>
&loglines;
</log>
Lines file (in this example, named loglines.xml):
<logline date="2007-07-01 13:56:04.313" text="start process" />
<logline date="2007-07-01 13:56:25.837" text="do something" />
<logline date="2007-07-01 13:56:25.853" text="the end" />
You can then append new lines to the 'lines file', but (most) XML parsers will be able to open the header file and read the lines correctly.
Filip notes that: This XML will not be parsed correctly by every XML parser on the planet. But all the parsers I have used do it correctly.
The big difference is the way you are thinking about your log data. In plain text files you are indeed just adding new lines. XML is a tree structure however, and you need to think about like such. What you are adding is probably another NODE, i.e.:
<log>
<time>12:30:03 PST</time>
<user>joe</user>
<action>login</action>
<log>
Because it is a tree what you need to ask is what parent are you adding this new node to. This is usually all defined in your DTD (Aka, how you are defining the structure of your data). Hopefully this is more helpful then just what library to use as once you understand this principle the interface of the library should make more sense.
Why reinvent the wheel? Use TraceSource Class (System.Diagnostics) with the XmlWriterTraceListener.
Sorry to post a answer for old thread. i developed the same long time ago. here i like to share my full code for logger saved log data in xml file date wise.
logger class code
using System.IO;
using System.Xml;
using System.Threading;
public class BBALogger
{
public enum MsgType
{
Error ,
Info
}
public static BBALogger Instance
{
get
{
if (_Instance == null)
{
lock (_SyncRoot)
{
if (_Instance == null)
_Instance = new BBALogger();
}
}
return _Instance;
}
}
private static BBALogger _Instance;
private static object _SyncRoot = new Object();
private static ReaderWriterLockSlim _readWriteLock = new ReaderWriterLockSlim();
private BBALogger()
{
LogFileName = DateTime.Now.ToString("dd-MM-yyyy");
LogFileExtension = ".xml";
LogPath= Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location) + "\\Log";
}
public StreamWriter Writer { get; set; }
public string LogPath { get; set; }
public string LogFileName { get; set; }
public string LogFileExtension { get; set; }
public string LogFile { get { return LogFileName + LogFileExtension; } }
public string LogFullPath { get { return Path.Combine(LogPath, LogFile); } }
public bool LogExists { get { return File.Exists(LogFullPath); } }
public void WriteToLog(String inLogMessage, MsgType msgtype)
{
_readWriteLock.EnterWriteLock();
try
{
LogFileName = DateTime.Now.ToString("dd-MM-yyyy");
if (!Directory.Exists(LogPath))
{
Directory.CreateDirectory(LogPath);
}
var settings = new System.Xml.XmlWriterSettings
{
OmitXmlDeclaration = true,
Indent = true
};
StringBuilder sbuilder = new StringBuilder();
using (StringWriter sw = new StringWriter(sbuilder))
{
using (XmlWriter w = XmlWriter.Create(sw, settings))
{
w.WriteStartElement("LogInfo");
w.WriteElementString("Time", DateTime.Now.ToString());
if (msgtype == MsgType.Error)
w.WriteElementString("Error", inLogMessage);
else if (msgtype == MsgType.Info)
w.WriteElementString("Info", inLogMessage);
w.WriteEndElement();
}
}
using (StreamWriter Writer = new StreamWriter(LogFullPath, true, Encoding.UTF8))
{
Writer.WriteLine(sbuilder.ToString());
}
}
catch (Exception ex)
{
}
finally
{
_readWriteLock.ExitWriteLock();
}
}
public static void Write(String inLogMessage, MsgType msgtype)
{
Instance.WriteToLog(inLogMessage, msgtype);
}
}
Calling or using this way
BBALogger.Write("pp1", BBALogger.MsgType.Error);
BBALogger.Write("pp2", BBALogger.MsgType.Error);
BBALogger.Write("pp3", BBALogger.MsgType.Info);
MessageBox.Show("done");
may my code help you and other :)
Without more information on what you are doing I can only offer some basic advice to try.
There is a method on most of the XML objects called "AppendChild". You can use this method to add the new node you create with the log comment in it. This node will appear at the end of the item list. You would use the parent element of where all the log nodes are as the object to call on.
Hope that helps.
XML needs a document element (Basically top level tag starting and ending the document).
This means a well formed XML document need have a beginning and end, which does not sound very suitable for logs, where the current "end" of the log is continously extended.
Unless you are writing batches of self contained logs where you write everything to be logged to one file in a short period of time, I'd consider something else than XML.
If you are writing a log of a work-unit done, or a log that doesn't need to be inspected until the whole thing has finished, you could use your approach though - simply openfile, write the log lines, close the file when the work unit is done.
For editing an xml file, you could also use LINQ. You can take a look on how here:
http://www.linqhelp.com/linq-tutorials/adding-to-xml-file-using-linq-and-c/