C# Discussion Boards - CodeProject

Re: lock some text files

Eddy Vluggen27-Oct-09 8:14

Eddy Vluggen

27-Oct-09 8:14

reza assar wrote:
i want to lock some text file in the specified directory
just two applications can access these files

Locking a file based on the application that's used for opening it is not supported by the file systems that I know.

reza assar wrote:
what should i do?

Review the specifications and research alternative solutions. Here's some to get you started;

* Is it necessary to 'lock' the file, or are you trying to prevent other people from reading the file? If the latter is the case, then try encrypting your text before you send it to the file.

* Could a container be used? You can store multiple documents in a zipfile, and protect them with a password.

* If speed is more important than having a textfile, consider using a dekstop-database like SQL CE.

HTH Smile | :)

I are Troll Suspicious | :suss:

Re: lock some text files

reza assar9-Nov-09 18:36

reza assar

9-Nov-09 18:36

i what to prevent users from "writing" and "reading" !!!! one application grant to write it and my application grant to read it but prevent other users from writing is more more important that reading! it may damage my application information
is there any other way?

Re: lock some text files

Eddy Vluggen10-Nov-09 3:42

Eddy Vluggen

10-Nov-09 3:42

reza assar wrote:
is there any other way?

So you're just trying to hide what's in the file from the user? In that case, go for zipfiles, a database or plainly encrypt the data.

No other methods that come to mind right now.

I are Troll Suspicious | :suss:

ADO.NET Entity Framework

Pankaj Saha27-Oct-09 1:27

Pankaj Saha

27-Oct-09 1:27

Hi, I am fetching the recored with a sql procedure, which returns a collection of values with the help of ADO.NET Entity framework. Now if I need to use stored procedure then I have to import that procedure in my .edmx file and map with a entity.
Now the problem is that, I am fetching the records with inner join that's why it can not be map any single Entity. Is it compulsory to map the sotred procedure to an Entity? Can we use stored procedure without mapping with an Entity ?

Pankaj

Re: ADO.NET Entity Framework

Not Active27-Oct-09 2:12

Not Active

27-Oct-09 2:12

You can create an entity in the designer that maps to multiple tables then map the stored proc to it. Otherwise, yes you can use stored procs. Check here[^] for some use extensions and samples.

only two letters away from being an asset

active single instance only

reza assar27-Oct-09 1:24

reza assar

27-Oct-09 1:24

hi i want to develop an application that , user could not execute more than one instance at a time
for example my application name is: "APP" . if some one click APP icon it will be run if there is no another instance running at the current machine
what should i do?
thanks in advance!

Re: active single instance only

N a v a n e e t h27-Oct-09 1:28

N a v a n e e t h

27-Oct-09 1:28

Take a look at Mutex[^] class.

Best wishes,
Navaneeth

Re: active single instance only

Hristo-Bojilov27-Oct-09 1:58

Hristo-Bojilov

27-Oct-09 1:58

You need to be very careful when you are using globally available mutexes running on limited OS accounts.
Maybe finding all processes with the same name like the current will be better and safer solution because doesn't require any special permissions.

Life is a stage and we are all actors!

Re: active single instance only

N a v a n e e t h27-Oct-09 2:10

N a v a n e e t h

27-Oct-09 2:10

Hristo Bojilov wrote:
You need to be very careful when you are using globally available mutexes running on limited OS accounts

What problems are you seeing?

Best wishes,
Navaneeth

Re: active single instance only

Hristo-Bojilov27-Oct-09 2:22

Hristo-Bojilov

27-Oct-09 2:22

The method System.Threading.Mutex.OpenExisting could throw UnauthorizedAccessException for sample.Will this method work when the current account doesn't have the desired access and cannot acquire it?I've used this mutexes method for my current project but after discovering this exception is thrown to often when running on limited accounts I had removed it and used just simple scan for the running processes which queries Windows performance counter API.

Life is a stage and we are all actors!

Re: active single instance only

Luc Pattyn27-Oct-09 4:16

Luc Pattyn

27-Oct-09 4:16

Hi,

I haven't used the managed mutex class yet, however it seems to me the MutexSecurity parameter in one of the constructors should be the key to solving the problems you've had.

Anyway, relying on GetProcessesByName() does not seem right as:
1. when a user renames an EXE, the resulting process would also be getting a different name;
2. I expect the Process methods also can fail when you have insufficient rights.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Re: active single instance only

anishkannan27-Oct-09 1:47

anishkannan

27-Oct-09 1:47

try this code.... this is for just check ur Exe application name is currently running or not

[DllImport("user32.dll", EntryPoint = "SetForegroundWindow")]
static extern IntPtr SetForegroundWindow(IntPtr hWnd);

private static bool AppIsAlreadyRunning()
{
Process c = Process.GetCurrentProcess();
foreach (Process p in Process.GetProcessesByName(c.ProcessName))
{
if (p.Id != c.Id)
{
if (p.MainModule.FileName.ToLower().Equals(c.MainModule.FileName.ToLower()))
{
SetForegroundWindow(p.MainWindowHandle);
return true;
}
}
}
return false;
}

Re: active single instance only

vtchris-peterson28-Oct-09 5:43

vtchris-peterson

28-Oct-09 5:43

I've implemented a few ways of doing this, each with various limitations. Then, I came across this solution which works great: http://dotnetperls.com/single-instance-windows-form[^]

Re: active single instance only

reza assar9-Nov-09 18:41

reza assar

9-Nov-09 18:41

thanks for your attention but the link is not refer correctly please to fix it!

Re: active single instance only

vtchris-peterson10-Nov-09 3:42

vtchris-peterson

10-Nov-09 3:42

Link works fine for me.

Google C# Single-Instance Windows Form by Sam Allen.

How to Avoid Â in Excel while writing through C#

Bharti Vermani27-Oct-09 1:19

Bharti Vermani

27-Oct-09 1:19

Hi,
I am trying to populate an excel sheet with some data .

I do the following to write to an excel:

StreamWriter stream = null;
string separator = " ";
string latitude = "31°49.4515437’S";

using (stream = new StreamWriter("C:\abc.xls", false))
{
StringBuilder builder = new StringBuilder();

builder.AppendLine();
builder.Append("Position");
builder.Append(separator);
builder.Append(latitude);
stream.WriteLine(builder.ToString());
}

stream.Flush();
}

When I do the above I see some junk values like 31Â°49.4515437â€™S in my excel sheet.

How do I avoid it and get to see "31°49.4515437’S" in my excel sheet.

Thanks
BV

Re: How to Avoid Â in Excel while writing through C#

Gideon Engelberth27-Oct-09 3:23

Gideon Engelberth

27-Oct-09 3:23

You could set the encoding explicitly on the StreamWriter. Even though the default is UTF-8 on my machine, explicitly setting UTF-8 made the correct characters show up.

PS: That stream.Flush() is unnecessary because the using block has already taken care of flushing and closing the StreamWriter.
PPS: In the future, please use the "code block" button to enclose your code in <pre> tags to give it formatting and highlighting. This will make the code easier to read.

Re: How to Avoid Â in Excel while writing through C#

Bharti Vermani27-Oct-09 19:18

Bharti Vermani

27-Oct-09 19:18

Hi Engelberth,
Thanks for the response,
I shall take care of PS and PPS sections.
WhenI tried the below:

using (stream = new StreamWriter("C:/abc.xls", false, Encoding.UTF8))

by doing so the formatting further detoriatted, earlier I was able to see each element in different cells in my excel sheet, By doing the above everything got clubbed in one cell, also more unknown characters got added

Initailly my separator was 'tab', but looks like after adding Encoding.UTF8 it would add the eqivalent character code forthat in excel , Also theoriginal issue still remained

Regards
BV

Re: How to Avoid Â in Excel while writing through C#

Bharti Vermani27-Oct-09 19:26

Bharti Vermani

27-Oct-09 19:26

Hi,
I got the solution,
Adding it here so that if someone else needs it can use it.

We need to use Encoding.GetEncoding("Windows-1252")) and this sorts the issue.

Thnaks Engelberth as you gave me hint as to where I can dig more.

Regards
BV

Re: How to Avoid Â in Excel while writing through C#

bali40628-Jul-10 15:49

bali406

28-Jul-10 15:49

Thanks guys i was struck was a long time on this issue Encoding.GetEncoding("Windows-1252"))
sloved my issue

SQL Connection Problem

Emmet_Brown27-Oct-09 0:50

Emmet_Brown

27-Oct-09 0:50

Hello

I've got a comboBox and I want to make a query after a change in the selected item is done.

Inside the "comboBox1_SelectedIndexChanged" function, I wrote these:

string ogretisim;
ogretisim = comboBox1.Text;
SqlConnection conn = null;

conn = new Sqlconnection("Data Source = Veritabani.sdf");
conn.Open()
conn.Close();

I did not do the query yet, just to try.

In the runtime, conn.Open() gives an error like it cannot reach the server.

What can be the problem?

note:

I've tried all of these:

newSqlConnection("Data Source = baglanXXX");
newSqlConnection("Data Source = Veritabani.sdf");
newSqlConnection("Data Source = .\\Veritabani.sdf");
newSqlConnection("Data Source = VeritabaniDataSet.xsd");
newSqlConnection("baglanXXX");

("baglanXXX" is my connection string)

please someone help Frown | :(

Re: SQL Connection Problem

spiritboy27-Oct-09 1:01

spiritboy

27-Oct-09 1:01

try

new SqlConnection(@"Server = .\sqlexpress; database = YourDbName ; integrated security = sspi;");

Re: SQL Connection Problem

J4amieC27-Oct-09 1:05

J4amieC

27-Oct-09 1:05

How could you tell he was using sql express?

Re: SQL Connection Problem

J4amieC27-Oct-09 1:05

J4amieC

27-Oct-09 1:05

The problem is that you don't understand connection strings.

http://www.connectionstrings.com/[^] for info.

Re: SQL Connection Problem

Emmet_Brown27-Oct-09 1:13

Emmet_Brown

27-Oct-09 1:13

thank you for replies, I'll work on it a bit further,

thanks again =)

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