Hi,
In the MSDN the sample doesn't use the close() method. But I know that
in most languages you do need to use the close() method after reading
and writing to a file.
from MSDN:
public static void Main()
{
string path = @"c:\temp\MyTes t.txt";
try
{
if (File.Exists(pa th))
{
File.Delete(pat h);
}
using (StreamWriter sw = new StreamWriter(pa th))
{
sw.WriteLine("T his");
sw.WriteLine("i s some text");
sw.WriteLine("t o test");
sw.WriteLine("R eading");
}
using (StreamReader sr = new StreamReader(pa th))
{
while (sr.Peek() >= 0)
{
Console.WriteLi ne(sr.ReadLine( ));
}
}
}
catch (Exception e)
{
Console.WriteLi ne("The process failed: {0}",
e.ToString());
}
}
does the "Using" replaces the needing for Close() method? 7 9772
<Er********@gma il.comwrote:
In the MSDN the sample doesn't use the close() method. But I know that
in most languages you do need to use the close() method after reading
and writing to a file.
<snip>
does the "Using" replaces the needing for Close() method?
Yes. "using" is equivalent to a try/finally block which calls Dispose()
in the finally block.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too
The simple answer to your question is yes the 'using' statement does replace
the need for a 'Close'...
check out the definitions of the using keyword in c# http://www.c-sharpcorner.com/UploadF...Statement.aspx
The 2 classes you mention below - StreamReader & StreamWriter both implement
the IDisposable interface and you can use any class that implements this
interface in a 'using' statement.
These particular classes call 'Close' on the underlying stream object when
the Dispose method is called by the 'using' statement.
A 'using' statement is often called a try - catch - finally block, as in the
variable inside the 'using' statement is automatically wrapped into it's own
try - catch - finally block and the Dispose mehtod of the IDisposable
interface is always called in the finally statement.
HTH
Ollie Riches
<Er********@gma il.comwrote in message
news:11******** **************@ k78g2000cwa.goo glegroups.com.. .
Hi,
In the MSDN the sample doesn't use the close() method. But I know that
in most languages you do need to use the close() method after reading
and writing to a file.
from MSDN:
public static void Main()
{
string path = @"c:\temp\MyTes t.txt";
try
{
if (File.Exists(pa th))
{
File.Delete(pat h);
}
using (StreamWriter sw = new StreamWriter(pa th))
{
sw.WriteLine("T his");
sw.WriteLine("i s some text");
sw.WriteLine("t o test");
sw.WriteLine("R eading");
}
using (StreamReader sr = new StreamReader(pa th))
{
while (sr.Peek() >= 0)
{
Console.WriteLi ne(sr.ReadLine( ));
}
}
}
catch (Exception e)
{
Console.WriteLi ne("The process failed: {0}",
e.ToString());
}
}
does the "Using" replaces the needing for Close() method?
Hi,
Jon Skeet [C# MVP] wrote:
<Er********@gma il.comwrote:
>In the MSDN the sample doesn't use the close() method. But I know that in most languages you do need to use the close() method after reading and writing to a file.
<snip>
>does the "Using" replaces the needing for Close() method?
Yes. "using" is equivalent to a try/finally block which calls Dispose()
in the finally block.
About that, a question: I have this (pseudo)code that I want to refactor
using the "using" clause:
StreamWriter writer = null;
try
{
// ...
}
catch ( Exception ex )
{
logger.Log( ex.Message );
}
finally
{
if ( writer != null )
{
writer.Close();
writer.Dispose( );
}
}
How to code that with a "using"? How can I do something special in case
an Exception occurs?
Greetings,
Laurent
--
Laurent Bugnion [MVP ASP.NET]
Software engineering, Blog: http://www.galasoft-LB.ch
PhotoAlbum: http://www.galasoft-LB.ch/pictures
Support children in Calcutta: http://www.calcutta-espoir.ch
Laurent Bugnion [MVP] <ga*********@bl uewin.chwrote:
About that, a question: I have this (pseudo)code that I want to refactor
using the "using" clause:
<snip>
How to code that with a "using"? How can I do something special in case
an Exception occurs?
Either put a try/catch within the using statement, or outside it.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too
Hi Jon,
Jon Skeet [C# MVP] wrote:
Laurent Bugnion [MVP] <ga*********@bl uewin.chwrote:
>About that, a question: I have this (pseudo)code that I want to refactor using the "using" clause:
<snip>
>How to code that with a "using"? How can I do something special in case an Exception occurs?
Either put a try/catch within the using statement, or outside it.
Thanks. I thought of that already, just wanted to confirm. Question
though: The code would become something like:
using ( StreamWriter writer = new StreamWriter( ... ) )
{
try
{
// ...
}
catch ( Exception ex )
{
logger.Log( ex.Message );
throw; // Is that correct??
}
}
I think that I shouldn't rethrow the Exception, is that correct? The
"using" clause is a try/finally, not try/catch/finally?
Thanks,
Laurent
--
Laurent Bugnion [MVP ASP.NET]
Software engineering, Blog: http://www.galasoft-LB.ch
PhotoAlbum: http://www.galasoft-LB.ch/pictures
Support children in Calcutta: http://www.calcutta-espoir.ch
Laurent Bugnion [MVP] wrote:
Hi Jon,
Jon Skeet [C# MVP] wrote:
>Laurent Bugnion [MVP] <ga*********@bl uewin.chwrote:
>>About that, a question: I have this (pseudo)code that I want to refactor using the "using" clause:
<snip>
>>How to code that with a "using"? How can I do something special in case an Exception occurs?
Either put a try/catch within the using statement, or outside it.
Thanks. I thought of that already, just wanted to confirm. Question
though: The code would become something like:
using ( StreamWriter writer = new StreamWriter( ... ) )
{
try
{
// ...
}
catch ( Exception ex )
{
logger.Log( ex.Message );
throw; // Is that correct??
}
}
I think that I shouldn't rethrow the Exception, is that correct? The
"using" clause is a try/finally, not try/catch/finally?
Thanks,
Laurent
If you rethrow the exception or not depends on if you completely handled
it or not. If the code that called this method needs to know about the
exception, you should rethow it.
I haven't investigated if a using clause has a catch or not, but if it
has, it rethrows the exception. The point is that the using clause does
not consume exceptions.
--
Göran Andersson
_____ http://www.guffa.com
Hi,
Göran Andersson wrote:
If you rethrow the exception or not depends on if you completely handled
it or not. If the code that called this method needs to know about the
exception, you should rethow it.
I haven't investigated if a using clause has a catch or not, but if it
has, it rethrows the exception. The point is that the using clause does
not consume exceptions.
That confirms what I actually observed. Thanks.
Laurent
--
Laurent Bugnion [MVP ASP.NET]
Software engineering, Blog: http://www.galasoft-LB.ch
PhotoAlbum: http://www.galasoft-LB.ch/pictures
Support children in Calcutta: http://www.calcutta-espoir.ch This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: Joecx |
last post by:
Using vb.net, I am using Streamreader to read a text file and searching for a
line to delete, the I close the file and open it as a streamwriter so I can
put the new file back to disk without the line that I deleted. Can someone
tell me how I can do this without having to close the file first before
switching to streamwriter, because closing...
|
by: Jimbo |
last post by:
After I read or write a file with streamreader and streamwriter and I close
it with the Close method, does that automatically let go of the file so that
any other process can modify it?
In my form, I read from a small configuration file with streamreader and
close it with streamreader.Close(). In this same event, when I open it for...
|
by: Astronomically Confused |
last post by:
using System;
using System.Collections;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Threading;
class HttpProcessor
{
private Socket s;
|
by: ShadowOfTheBeast |
last post by:
Hi, I have got a major headache understanding streamReader and streamWriter
relationship.
I know how to use the streamreader and streamwriter independently.
but how do you write out using the streamwriter, what you have read into a
streamReader? and also can someone explain how they work in simple terms
--
The Matrix Insurrection
|
by: R.L. |
last post by:
See the code below, var 'content ' is suppose to be "Hello!", not "". Who
knows why? Thanks
----------------------------------------
string text = "hello!";
MemoryStream stream = new MemoryStream();
StreamWriter streamWriter = new StreamWriter(stream, Encoding.ASCII);
streamWriter.Write(text);
| |
by: mloichate |
last post by:
I must read a very heavy-weight text plain file (usually .txt
extension) )and replace a given character with another given character
in all text inside the file. My application was working pretty well
with this below shown code (code placed in a buttonclick event after
selecting the file in a normal OpenFileDialog):
...
|
by: vvenk |
last post by:
Hello:
When I use either one to read a Text file, I get the same result. The length
of the string that the file's content has been written into is the same.
However, if the file is binary, FileGet gets me the correct content while
StreamReader gives me a truncated string.
Can somebody advise me why? Should I be using BinaryReader...
|
by: LucaJonny |
last post by:
Hi,
I've got a problem using StreamReader in VB.NET.
I try to read a txt file that contains extended characters and theese
are removed from the line that is being read.
I've read a lot of articles about ANSI encoding like this
http://support.microsoft.com/default.aspx?scid=kb;en-us;889835
but System.Text.Encoding.Default don't work!!
|
by: Rob |
last post by:
Hi,
I have a VB.Net application that parses an HTML file. This file was an
MS Word document that was saved as web page.
My application removes all unnecessary code generated by MS Word and
does some custom formatting needed by my client.
I use a StreamReader to read in the file...regular expressions to parse
and clean up the file...and a...
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language...
| |
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it. ...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in...
|
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| |
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating...
| |