C# Discussion Boards - CodeProject

how to erase a file content with c# ?

cmpeng345-Jul-06 0:02

cmpeng34

5-Jul-06 0:02

hi all,
how can i erase entire content of a file with C# ?
want that file as if its newly created ?
thanks, bye.

Re: how to erase a file content with c# ?

stancrm5-Jul-06 0:09

stancrm

5-Jul-06 0:09

Just open it and save it.

StreamWriter s = new StreamWriter("test.txt");
s.Close();

Re: how to erase a file content with c# ?

engsrini5-Jul-06 0:13

engsrini

5-Jul-06 0:13

<br />
File.Create (@"C:\Test.txt"); <br />
<br />
//Give path of already created file. this will erase the content of file and create it as new file<br />

srini

LoaderLock Exception in .net 2.0

Waqas Nasir4-Jul-06 23:55

Waqas Nasir

4-Jul-06 23:55

hi,

I need some help regarding the loader lock exception in .net 2.0... I have a simple code which creates a new thread using threadstart delegate and creates a windows form in the thread and calls the show method of that form... the result is a loaderlock exception saying some unmanaged code is executed in managed area... has any body got something to say which could possibly solve the problem...

Thanks...

Regards,

Waqas.

datagrid problem "windows application"

chandra sagar4-Jul-06 23:46

chandra sagar

4-Jul-06 23:46

hi all,
i am working on a windows application using c#.net .
the scenario of my problem is, i am havin two controls textbox and datagrid.the datagrid contains one column which has all the countries names. now whenever i type the countries name in the textbox the focus should go on to that countries name in the datagrid. and the row which contains the country should be shown as the first row. for example if we have denmark as the country the focus should go to this whenever i type this in the textbox and we should be able to scroll down the datagrid and show denmark as the first row in the datagrid.

can any one help.

regards,
sagar

System Tray Icon with background processes [modified]

synunn4-Jul-06 23:40

synunn

4-Jul-06 23:40

Hi kids

Background

I'm writing a system service style application. It consists of a NotifyIcon in the sys'tray that has several functions that are called from the ContextMenu/Events.

When the app' starts it should do nothing but sit there until the 'Start Sending' MenuItem's Event is called. This event starts a new Thread which checks a file repository between Thread.Sleep(15*60*1000).

Problem

To cut to the chase, the application is maxing out the cpu usage during a loop:

while(this.Created){<br />
    Application.DoEvents();}

How to I prevent this excesive usage?

Do I need to access the System Idle Process?

This usage doesn't actually halt the server or even slow it down it just capitalizes the usage as there is no other contender for the cpu's attention. I have tried to drop the Thread.Priority to BelowNormal but the applications Thread remains at Normal in Task Manager.

-- modified at 5:41 Wednesday 5th July, 2006

Re: System Tray Icon with background processes

Guffa5-Jul-06 23:32

Guffa

5-Jul-06 23:32

Just make it sleep between the times it handles the messages:

while (this.Created) {<br />
   Application.DoEvents();<br />
   Thread.Sleep(100);<br />
}

---
b { font-weight: normal; }

Re: System Tray Icon with background processes [modified]

synunn6-Jul-06 6:34

synunn

6-Jul-06 6:34

I thought that too but it causes a crash, The problem is that Events don't stack up between each Sleep so you have to click during the split second that Application.DoEvents(); is running OMG | :OMG:

-- modified at 12:34 Thursday 6th July, 2006

Not to worry though, I found a solution

Re: System Tray Icon with background processes

Guffa6-Jul-06 11:58

Guffa

6-Jul-06 11:58

Yes, the messages are queued.

If the program crashes, there is something else that causes that.

---
b { font-weight: normal; }

Check for all installed .net frameworks

code4jigar4-Jul-06 23:11

code4jigar

4-Jul-06 23:11

How do i get information about all installed .net framework version? And On what framework my application is running?

Say I have application config file saying
<startup>
<supportedRuntime version="v1.0.3705" />
<supportedRuntime version="v1.1.4322" />
<supportedRuntime version="v2.0.50727" />
</startup>

So It will run on all the platform. Now, I want to check on which version its running and what all versions are installed on the system.

Re: Check for all installed .net frameworks

engsrini5-Jul-06 0:17

engsrini

5-Jul-06 0:17

use
System.Environment.Version

Wink | ;)

Srini

Re: Check for all installed .net frameworks

code4jigar5-Jul-06 3:16

code4jigar

5-Jul-06 3:16

it doesn't giv me what all versions are installed

Re: Check for all installed .net frameworks

S. Senthil Kumar5-Jul-06 5:10

S. Senthil Kumar

5-Jul-06 5:10

Does this[^] article help?

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: Check for all installed .net frameworks

code4jigar5-Jul-06 23:10

code4jigar

5-Jul-06 23:10

nice article but Can i do it through managed code? that is in c# ..?? even its Okei if i hav to read from registry. Where i can get these info ?
Thanks for help.

Re: Check for all installed .net frameworks

S. Senthil Kumar6-Jul-06 1:48

S. Senthil Kumar

6-Jul-06 1:48

Well, you could always wrap the unmanaged code in a C++/CLI class and use it from C#.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Re: Check for all installed .net frameworks

code4jigar5-Jul-06 19:50

code4jigar

5-Jul-06 19:50

It does not work because it just reads from sys parameter. It gives me info about where i am currently executing not about what all versions are installeed

An example on RowFilter Property of DataView object in C#

Alamzeb khan4-Jul-06 22:45

Alamzeb khan

4-Jul-06 22:45

i need a complete example on RowFilter property of DataView Object in C#

Re: An example on RowFilter Property of DataView object in C#

led mike5-Jul-06 5:07

led mike

5-Jul-06 5:07

They hide those examples in the DOCUMENTATION[^] WTF | :WTF:

RowFilter property of DataView object in C#

Alamzeb khan4-Jul-06 22:36

Alamzeb khan

4-Jul-06 22:36

how can i use RowFilter property of DataView object in C# to search a specific row?

Calling C# function from Java

ahjiang4-Jul-06 22:31

ahjiang

4-Jul-06 22:31

Hi all,

I'm relatively new to C# and now i would like to have the best of both worlds, Java and C#. I would like to know how is it possible for a Java program to call a function, for e.g. helloWorld() in a c# program.

Appreciate any simple examples or links to demonstrate the use.

Thanks

Re: Calling C# function from Java

Divyang Mithaiwala4-Jul-06 23:30

Divyang Mithaiwala

4-Jul-06 23:30

ahjiang wrote:
is it possible for a Java program to call a function, for e.g. helloWorld() in a c# program?

No.

Currently Java just support to call C/C++ native function through JNI(Java Native Interface). See this[^].

regards,
Divyang Mithaiwala
System Engineer & Software Developer

Re: Calling C# function from Java

stancrm5-Jul-06 0:11

stancrm

5-Jul-06 0:11

I think you are in the wrong forum. Try to post your question in Java Forum. Because the code what you want is a java code.

how to handle exported function from c++ in C#

Tugberk_Kara4-Jul-06 22:10

Tugberk_Kara

4-Jul-06 22:10

I have a c++ code including a method as

parsefile( FILE * pfile);

I have exported this method in c++ in a dll. But In my c# code I want to use this method.
Thus, I have written the below code in the cs file.

[DllImport("main.dll")]
public extern static void parseFile( File pfiOriginal );

static void Main(string[] args)
{
/**** I don't know how to handle FILE * here because there is no FILE *
in c#. deneme.pqd is my file to be used by parsefile method.The
compiler gives error that File constructor takes no arguments.
*****/

File a = new File("deneme.pqd");
parseFile(a);

Console.WriteLine("Press any key to continue...");
Console.ReadLine();
}

Please can you help me urgently about a method doing this.

Re: how to handle exported function from c++ in C#

stancrm4-Jul-06 22:26

stancrm

4-Jul-06 22:26

I think the structure FILE and class File is complete different.
If you have a structure called FILE, then copy it to C#.

struct FILE
{
   ...
}

then try to use this code:

[DllImport("main.dll")]
public extern static void parseFile([MarshalAs(UnmanagedType.Struct)]FILE pfiOriginal );

Re: how to handle exported function from c++ in C#

Tugberk_Kara4-Jul-06 22:41

Tugberk_Kara

4-Jul-06 22:41

I have no structure called FILE. It is a C File I/O. So it is a a FILE pointer such as FILE *fp.

What should I do then????

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