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Edit: how about this?
static bool IsText(byte[] data)
{
if (data.Length < 16)
throw new Exception("Data is too short to guess the encoding");
byte asciitester = 0;
for (int i = 0; i < data.Length; i++)
asciitester |= data[i];
if (asciitester < 0x80)
return true;
if (IsValidUTF8(data))
return true;
if (IsValidUTF16(data))
return true;
return false;
}
static bool IsValidUTF16(byte[] data)
{
if ((data.Length & 1) == 1)
return false;
bool LittleEndian;
ushort BOM = BitConverter.ToUInt16(data, 0);
if (BOM == 0xFFFE)
LittleEndian = false;
else if (BOM == 0xFEFF)
LittleEndian = true;
else
return false;
bool SecondOfSurrogatePair = false;
for (int i = 2; i < data.Length; i+=2)
{
int code;
if (LittleEndian)
code = data[i] | (data[i + 1] << 8);
else
code = (data[i] << 8) | data[i + 1];
if (SecondOfSurrogatePair)
{
if (code < 0xDC00 || code > 0xDFFF)
return false;
SecondOfSurrogatePair = false;
}
else
{
if (code >= 0xD800 && code <= 0xDBFF)
SecondOfSurrogatePair = true;
}
}
return SecondOfSurrogatePair;
}
static bool IsValidUTF8(byte[] data)
{
int index = 0;
if (data[0] == 0xEF)
{
if (data[1] != 0xBB ||
data[2] != 0xBF)
return false;
index = 3;
}
int mode = 0;
for (int i = index; i < data.Length; i++)
{
switch (mode)
{
case 0:
if (data[i] < 0x80)
break;
else if (data[i] < 0xC0)
return false;
else if (data[i] < 0xE0)
mode = 1;
else if (data[i] < 0xF0)
mode = 2;
else if (data[i] < 0xF5)
mode = 3;
else
return false;
break;
case 1:
case 2:
case 3:
if (data[i] < 0x80 || data[i] >= 0xC0)
return false;
mode--;
break;
default:
return false;
}
}
return mode == 0;
}
I suppose you could tests to see if there are any unprintable characters, too.
modified on Monday, April 5, 2010 2:02 PM
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Btw, could I get some feedback on code this, please? Specifically on whether the result is correct as far as it tests, this test is "supposed to" be very optimistic in what it accepts as text, so I'm especially interested in whether there are valid UTF-16 or UTF-8 strings that get rejected by the test. I'm not exactly a Unicode expert..
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This isn't going to work in all cases since there is no requirement for a text file to have byte order marks. Also, what if the binary file just happens to have those very bytes in the place where you would normally have byte order marks?
What do you do if there are NO byte order marks (which is most text files anyway...)?
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Hey, what happened to DOS/Windows marking the End Of File with Ctrl+Z (26) when it's a text file? 
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That character never made it into the text file. I only ever saw it used when copying from CON to a file. Ctrl-Z just denoted the end of the stream that was being typed.
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Text mode reading wouldn't return it, but I used to see it when reading text files in binary mode.
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That is not in general possible, you can at best make a "pretty good guess".
For example you can first check whether the file is a valid UTF-8 string, if the file is sufficiently big the chance is very small that a non-text file is accidentally valid UTF-8.
But you can't be quite sure, an invalid UTF-8 string could be made invalid because it is slightly corrupted or badly encoded and still "be"* text, and a binary file could accidentally (although the chance is quite small) be valid UTF-8.
Btw, ASCII files will validate as valid UTF-8.
And you could add some other things, such as checking for a byte order mark and/or UTF-16
* let's not argue about the meaning of "being a text file", but there are several ways to look at it, for example "if it can be decoded to text, it is a text file regardless of whether the text is meaningful" or "if and only if it was originally written as a text file, it is a text file"
If you know the text is going to be in a particular language you have some more options, such as checking the statistical properties of the text against expected values based on the language - that is still no sure-fire way to know whether something is actually text or even to reject all non-text, though.
No matter what you do with the result of the "text test", it had better be robust enough to handle "accidental non-text", and having a "I am sure this is text, do it anyway" option may be useful too.
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I think if I ever need to create a binary file format, I'll be sure to start it with 0xFFFE. 
harold aptroot wrote: "if and only if it was originally written as a text file, it is a text file"
That's my point of view.
I still want to know why the original poster wants to do this.
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Win! 
For extra points, make the rest of the file valid UTF-16 
PIEBALDconsult wrote:
I still want to know why the original poster wants to do this.
Yea me too, I always get curious when people want to do things that are theoretically impossible. Which this is. I'd also like to know whether he's going to put in his own, rather brittle, test.. and I'll admit that my own code isn't that much better
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Read in the file assuming it is text. Check for common words, like "is", "it", "or", "the", "that", "they", or any word you might expect to be in the text file (the bigger the smallest word you check for, the more accurate the check will be). Then check the text to ensure it only contains the characters that you can type on a keyboard (numbers, letters, punctuation). That should give you an ok guess as to whether or not it is a text file (which contains english text), without causing you too much work.
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Hi all,
I just found out that there are many .lnk parser in C++/C/Java, but I am wondering if there is any reference code on this topic for C#.
Thanks a lot!
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I use .Net version 2.0. I recently implemented double buffering in an animation-heavy aspect of my application--instead of drawing directly to the screen I copy the screen to a Bitmap, use a graphics object to draw on the bitmap, and copy the bitmap back to the screen. It has made the animation faster and smoother. The code looks like this:
Bitmap offScreenBmp;
Graphics offScreenDC;
offScreenBmp = new Bitmap(this.Width, this.Height);
offScreenDC = Graphics.FromImage(offScreenBmp);
// I do drawing in offScreenDC
// I do drawing in offScreenDC
// I do drawing in offScreenDC
Graphics clientDC = this.CreateGraphics();
clientDC.DrawImage(offScreenBmp, 0, 0);
It works perfectly in most situations. However, if I use remote desktop to access a computer on which my application is running (which I often do) I notice that there is this awful white flicker that happens every time I copy my bitmap to the screen. The flicker occurs wherever my bitmap has been changed by its Graphics, and I assume it's some sort of clearing the screen action that happens before every copy, and it just happens too quickly for me to see when I'm not using RDP.
Does anyone know how to avoid this or turn it off? I would really like to keep using this new technique.
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Basically i was told to write a file watcher.
what i need is a configuration files that edit the watch path inside the .exe application?
Get the previous time and date this application had run.
This is the code that i haven wrote so far. Also asking if anyone is willingly to be my personal mentor in coding.
<br />
public partial class frmNotifier : Form<br />
{<br />
private StringBuilder m_Sb;<br />
private bool m_bDirty;<br />
private System.IO.FileSystemWatcher m_Watcher;<br />
private bool m_bIsWatching;<br />
<br />
<br />
public frmNotifier()<br />
{<br />
InitializeComponent();<br />
m_Sb = new StringBuilder();<br />
m_bDirty = false;<br />
m_bIsWatching = false;<br />
<br />
<br />
<br />
<br />
RegistryKey rkApp = Registry.LocalMachine.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true);<br />
rkApp.SetValue("MyApp", Application.ExecutablePath.ToString());<br />
<br />
}<br />
<br />
private void frmNotifier_Load(object sender, EventArgs e)<br />
{<br />
string date,time;<br />
date =DateTime.Now.ToString("dd/MM/yyyy");<br />
time = DateTime.Now.ToString("hh:mm:sstt");<br />
<br />
lstNotification.Items.Add("Program executed at: " + date+" , " + time);<br />
<br />
m_bIsWatching = true;<br />
m_Watcher = new System.IO.FileSystemWatcher();<br />
m_Watcher.Filter = "*.*";<br />
m_Watcher.Path = "D:\\TEMP\\";<br />
m_Watcher.IncludeSubdirectories = true;<br />
m_Watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite<br />
| NotifyFilters.FileName | NotifyFilters.DirectoryName;<br />
m_Watcher.Changed += new FileSystemEventHandler(OnChanged);<br />
m_Watcher.Created += new FileSystemEventHandler(OnChanged);<br />
m_Watcher.Deleted += new FileSystemEventHandler(OnChanged);<br />
m_Watcher.Renamed += new RenamedEventHandler(OnRenamed);<br />
m_Watcher.EnableRaisingEvents = true;<br />
<br />
}<br />
<br />
<br />
private void OnChanged(object sender, FileSystemEventArgs e)<br />
{<br />
<br />
if (!m_bDirty)<br />
{<br />
m_Sb.Remove(0, m_Sb.Length);<br />
m_Sb.Append(e.FullPath);<br />
m_Sb.Append(" ");<br />
m_Sb.Append(e.ChangeType.ToString());<br />
m_Sb.Append(" ");<br />
m_Sb.Append(DateTime.Now.ToString());<br />
m_bDirty = true;<br />
}<br />
}<br />
<br />
private void OnRenamed(object sender, RenamedEventArgs e)<br />
{<br />
if (!m_bDirty)<br />
{<br />
m_Sb.Remove(0, m_Sb.Length);<br />
m_Sb.Append(e.OldFullPath);<br />
m_Sb.Append(" ");<br />
m_Sb.Append(e.ChangeType.ToString());<br />
m_Sb.Append(" ");<br />
m_Sb.Append("to ");<br />
m_Sb.Append(e.Name);<br />
m_Sb.Append(" ");<br />
m_Sb.Append(DateTime.Now.ToString());<br />
m_bDirty = true;<br />
<br />
}<br />
}<br />
<br />
private void tmrEditNotify_Tick(object sender, EventArgs e)<br />
{<br />
if (m_bDirty)<br />
{<br />
lstNotification.BeginUpdate();<br />
lstNotification.Items.Add(m_Sb.ToString());<br />
lstNotification.EndUpdate();<br />
m_bDirty = false;<br />
}<br />
}<br />
<br />
<br />
<br />
<br />
<br />
<br />
private void frmNotifier_Resize(object sender, EventArgs e)<br />
{<br />
if (this.WindowState == FormWindowState.Minimized)<br />
{
if (this.WindowState == FormWindowState.Minimized)
{
Hide();
FileChangeWatcher.Visible = true;
Thread.Sleep(1000);
}<br />
<br />
}<br />
}<br />
<br />
private void notifyIcon1_MouseDoubleClick(object sender, MouseEventArgs e)<br />
{<br />
Show();
this.WindowState = FormWindowState.Normal;
FileChangeWatcher.Visible = false;
}<br />
<br />
private void frmNotifier_FormClosing(object sender, FormClosingEventArgs e)<br />
{<br />
m_bIsWatching = false;<br />
m_Watcher.EnableRaisingEvents = false;<br />
m_Watcher.Dispose();<br />
<br />
string date, time,date1,time1;<br />
<br />
date =DateTime.Now.ToString("ddMMyyyy");<br />
time = DateTime.Now.ToString("hhmm tt");<br />
<br />
if (Directory.Exists("c:\\FileChangeLog"))<br />
{<br />
<br />
<br />
<br />
}<br />
else {<br />
Directory.CreateDirectory("C:\\FileChangeLog");<br />
}<br />
<br />
<br />
StreamWriter sw = new StreamWriter(@"c:\FileChangeLog\" + date + "@" + time + "log.txt");<br />
<br />
date1 = DateTime.Now.ToString("dd/MM/yyyy");<br />
time1 = DateTime.Now.ToString("hh:mm:ss:tt");<br />
lstNotification.Items.Add("Program ended at: " + date1 + " , " + time1);<br />
<br />
foreach (string sItem in lstNotification.Items)<br />
{<br />
sw.WriteLine(sItem);<br />
}<br />
sw.Close();<br />
}<br />
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1) Read the bit at the top of the page: "How to get an answer".
2) Don't post your entire app - no-one is going to read it.
3) If you post code, use the "code block" widget (or <pre> </pre> codes) to preserve the formatting. The difference is:
private void frmNotifier_FormClosing(object sender, FormClosingEventArgs e)<br />
{<br />
m_bIsWatching = false;<br />
m_Watcher.EnableRaisingEvents = false;<br />
m_Watcher.Dispose();<br />
<br />
string date, time,date1,time1;<br />
<br />
date =DateTime.Now.ToString("ddMMyyyy");<br />
time = DateTime.Now.ToString("hhmm tt");<br />
<br />
if (Directory.Exists("c:\\FileChangeLog"))<br />
{<br />
<br />
<br />
<br />
}<br />
else {<br />
Directory.CreateDirectory("C:\\FileChangeLog");<br />
}<br />
<br />
<br />
StreamWriter sw = new StreamWriter(@"c:\FileChangeLog\" + date + "@" + time + "log.txt");<br />
<br />
date1 = DateTime.Now.ToString("dd/MM/yyyy");<br />
time1 = DateTime.Now.ToString("hh:mm:ss:tt");<br />
lstNotification.Items.Add("Program ended at: " + date1 + " , " + time1);<br />
<br />
foreach (string sItem in lstNotification.Items)<br />
{<br />
sw.WriteLine(sItem);<br />
}<br />
sw.Close();<br />
}and
private void frmNotifier_FormClosing(object sender, FormClosingEventArgs e)
{
m_bIsWatching = false;
m_Watcher.EnableRaisingEvents = false;
m_Watcher.Dispose();
string date, time,date1,time1;
date = DateTime.Now.ToString("ddMMyyyy");
time = DateTime.Now.ToString("hhmm tt");
if (Directory.Exists("c:\\FileChangeLog"))
{
}
else
{
Directory.CreateDirectory("C:\\FileChangeLog");
}
StreamWriter sw = new StreamWriter(@"c:\FileChangeLog\" + date + "@" + time + "log.txt");
date1 = DateTime.Now.ToString("dd/MM/yyyy");
time1 = DateTime.Now.ToString("hh:mm:ss:tt");
lstNotification.Items.Add("Program ended at: " + date1 + " , " + time1);
foreach (string sItem in lstNotification.Items)
{
sw.WriteLine(sItem);
}
sw.Close();
}Which would you rather read?
4) Be specific. What is your problem, not "some-one write it for me".
You should never use standby on an elephant. It always crashes when you lift the ears. - Mark Wallace
C/C++ (I dont see a huge difference between them, and the 'benefits' of C++ are questionable, who needs inheritance when you have copy and paste) - fat_boy
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The esteemed John Simmons has written a great FileSystemWatcher class. Read his article here[^].
Don't blame me. I voted for Chuck Norris.
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Hi,
I need to write an automated C# code to send the emails to the distribution list of an exchange server .
I have tried with the SmtpClient class.But it was giving an error saying "Failure sending mail."
Plz help me on this,
Thanks in Advance,
Ravi.
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See here.
Me, I'm dishonest. And a dishonest man you can always trust to be dishonest.
Honestly. It's the honest ones you want to watch out for...
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Hi,
I have ATL COM exe(out-of-proc) server which I want to use in c# .net client.
Somebody tell me how to use this in C#? I know how to use COM dll in C#. But I am not sure how to use out-of-proc in C# client?
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Hi,
I am trying to write a windows service which is used to pull some data on the network(Intranet) for regular intervals (for every 30 minutes). but i am very new to this. i googled on the internet but i found all the samples on Service Account type=localsysatem but not the Network.
can any one give me some sample example how we can pull data on network?
even i just tried a sample to make a log entry with in the localsystem for every 5 minutes. but it makes any entry when you stop or start service manually but its not doing that automatically. even i set the property "SrartType" of serviceinstaller to 'Automatic'.
can any one please help me??
fttyhtrhyfytrytrysetyetytesystryrty
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The account used doesn't change the code. All you're doing is tell the service which account to login to the system with. Since you're using network resources, this account would have to have permissions to those resources. LocalSystem doesn't have any permissions to anything off of, well, the Local System the service is running on, so it will not be able to get to any network shares or whatever.
What do you mean by "how we can pull data on network"? Where is the data coming from? What kind of server? Is there authentication involved? ...
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Have your domain admins create a user specifically for this Service and use that.
yadlaprasad wrote: every 30 minutes
That may not be frequent enough to warrent a Windows Service. You could try a Scheduled Task and see how that works.
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Hello all,
I would appreciate any help that can be given. I'm new to c# and mostly develop in c++. I'm using Microsoft Visual Studio 2010 as my IDE. My question is I'd like to ouput cars from a car collection. I'm using a 3rd party DLL library. As far as I know the dll has 2 classes. They are CarCollection and Car.
CarCollection has the following functions:
using System;
using System.Collections.Generic;
namespace CaraPartnersSdk
{
public class CarCollection
{
public CarCollection();
public IEnumerable<Car> FindByName(string name);
public Car GetByID(int id);
}
}
Car.cs:
using System;
using System.Collections.Generic;
namespace CaraPartnersSdk
{
public class Car
{
public Car();
public string AlternateForm { get; }
public Condition Condition { get; }
public IEnumerable<Car> ConnectsToCars { get; }
public bool HasBeenOpened { get; }
public int ID { get; }
public string Name { get; }
public string OptionalAttributesXml { get; }
public decimal Price { get; }
public string Set { get; }
public int Strength { get; }
}
}
All I'm trying to do is output each Car's name and ID which is in the dll. For now, I'm using a simple main class. I have no idea how to iterate through the CarCollection since it's not an array or actual collection. I'm doing CarCollection aCollection = new CarCollection(); When I use aCollection.FindByName() I get a message which does not help. After that I'm stumped. I know I have to use public IEnumerable<Car> FindByName(string name); from the CarCollection class but I have no idea how. I wish they passed the collection as an array because then I can do a simple for loop like
for(int i = 0; i
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adrian564 wrote: I get a message which does not help
Can you post the message here?
Me, I'm dishonest. And a dishonest man you can always trust to be dishonest.
Honestly. It's the honest ones you want to watch out for...
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Hello all,
I would appreciate any help that can be given. I'm new to c# and mostly develop in c++. I'm using Microsoft Visual Studio 2010 as my IDE. My question is I'd like to ouput cars from a car collection. I'm using a 3rd party DLL library. As far as I know the dll has 2 classes. They are CarCollection and Car.
CarCollection has the following functions:
using System;
using System.Collections.Generic;
namespace CaraPartnersSdk
{
public class CarCollection
{
public CarCollection();
public IEnumerable<Car> FindByName(string name);
public Car GetByID(int id);
}
}
Car.cs:
using System;
using System.Collections.Generic;
namespace CaraPartnersSdk
{
public class Car
{
public Car();
public string AlternateForm { get; }
public Condition Condition { get; }
public IEnumerable<Car> ConnectsToCars { get; }
public bool HasBeenOpened { get; }
public int ID { get; }
public string Name { get; }
public string OptionalAttributesXml { get; }
public decimal Price { get; }
public string Set { get; }
public int Strength { get; }
}
}
All I'm trying to do is output each Car's name and ID which is in the dll. For now, I'm using a simple main class. I have no idea how to iterate through the CarCollection since it's not an array or actual collection. I'm doing CarCollection aCollection = new CarCollection(); When I use aCollection.FindByName() I get a message which does not help. After that I'm stumped. I know I have to use public IEnumerable<Car> FindByName(string name); from the CarCollection class but I have no idea how. I wish they passed the collection as an array because then I can do a simple for loop like
for(int i = 0; i
{
collection(i).getName();
}
something like that, but I guess thats not the case. Please I would appreciate any help. Thanks.
-Adrian
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hi,
this might be one of the way to solve it. you can use LINQ query to do it in a neat way
IEnumerable<string> carnames = from cars in car
select cars.name;
foreach(string cr in carnames)
{
//do whatever with cr
}
i feel linq is really a nice concept introduced.. infact i have become a fan of it.
in above u can specify the 'where' condition also as per your need..
Hope this helps u...
Regards
Samir
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