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I agree with Mark - except I would use a application settings file for the connection string, rather than a constant. That way, you don't have to change the software when you do go to multi-user, just the app.settigns file. You can also test your software on an off-line database while the production one is untouched.
As for the SQL Injection - Mark is spot on. Look at the MySqlCommand.AddWithValue method for details. It makes life a lot simpler than string concatenation.
ListViewItem item = new ListViewItem("" + rdr[0]);
item.SubItems.Add("" + rdr[1]);
item.SubItems.Add("" + rdr[2]);
It doesn't work because DateReader returns an object - you have to cast it to an appropriate data type. For example
ListViewItem item = new ListViewItem((string) rdr[0]);
item.SubItems.Add((int) rdr[1]);
item.SubItems.Add((float) rdr[2]);
By adding the empty string, you are forcing an implicit string conversion via the default ToString implementation. This may not be what you want in all cases...
When it comes to updates, and distributing them, I am afraid you will have to poll for them as Mark sugested. Use a timer, so you aren't looking all the time, and probably set a table with a last update column. Then you only have to read a single row in order to tell if you are up to date. Nasty, but better than reading an entire table.
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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thanks for reply. i forgot about casting things... i knew about it since C++... there are something similar... well know i know 
about updates... tell me then what is the best to have (server, database) for my app to work?
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i just found something called SqlCE, it's a small database, and it can hold whole database in one single file up to 4Gb in size... the .sdf file can be encrypted with 128-bit encryption for data security so that's how i could keep sensitive info (login, pwd) safe. what you think?
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Regretably, not a good idea - SQLCe is a good DB system, but it is only single user. You will have huge problems if you try to have multiple users access it. Worse, these problems may be intermittent.
If you want multi-user access, then stick with one of the big boys (SQL, MySql)
It is unusual to store passwords, mostly you would store a hash of the password instead - MD5 is common but should not be used for new projects as it is considered "broken". Try a google for SHA-2 which is .NET supported. The reasoning for this is that it is "impossible" to reverse the hash and work out a typeable password that matches the stored hash value.
Note: "Impossible" is why MD5 is considered broken - it has been shown that you can reverse it.
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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i haven't said it properly... i DO have SQL Server 2008, SQLce - it's just a little DB for my app settings! nothing else, just settings. it could keep my passwords in it. that's the only reason i want to use it. but now i still have some doubts.
imagine i open some sort of properties window in my app. it has 2 text fields in it. "login" and "password". it should tell what's what in it, login can be seen untouched, but the password field will be kind of "**********". if i will keep SHA1 version of my password in my settings file (xml) then it's great, SHA1 version can't be used by anyone. but what will be sent to the server upon request? SHA1 version? well isn't it going to be wrong password? help me please to figure it out, i'm lost.
i DO want to change some settings FROM my app, but i DON'T want them (settings) to be seen anywhere outside of my app... so what to do?
i know about encrypting, but for it to be decrypted i need a password that i used to encrypt. right? well i have just one choice - is to hardcode it in my app, as a string value i guess? isn't true that anyone who knows what disassembler is can read my hardcoded password to decrypt the whole settings file? again, i'm lost 
ps: since i'm running SQL server 2008 is there any advantages i have already to update my listview?
added: exploring SqlDependency Class
modified on Monday, September 6, 2010 9:37 AM
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Can anyone suggest .NET based open source Rule Engine?
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This[^] is one. I have not used it though.
You can try out workflow foundation if that fits your need.
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Hello everyone,
I have a control update problem where I am unable to update a progress bar during a loop.
I have a winform object in C# which contains a progress bar. The program interfaces with a C++ DLL through the use of delegates. I have a simple dumb loop on the C++ side (which simply calls back to update the progress bar value). The loop is as follows:
HANDLE handle = CreateProgressDialog();
for (int i = 0; i < 100000; ++i)
{
int val = i%100;
SetProgressValue(handle, val+1);
}
On the C# side, it is as follows for the progress bar update function.
public void SetProgressValue(IntPtr handle, int value)
{
pdt.SetProgressValue(value);
pdt.Refresh();
}
Now, the update does not happen frequently enough and I never see the progress bar move beyond the value of 10. The progress bar moves fast as expected but it does not update all the times (and has a strange affinity for update when the progress value is low!). When I debug and step through, everything is fine. I am guessing this is because there is plenty of time to update...
Also, I even tried calls like System.Windows.Forms.Application.DoEvents() instead of update() but with no change.
I should mention that everything is called from the same thread (the loop and the SetProgressValue() calls).
When I use something like Thread.Sleep(100) at the end of SetProgressValue() function, it behaves better. However, I was wondering if there was a better way to achieve this.
I would appreciate any help you can give me.
Thanks,
Keith
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I suspect that your problem is caused by trying to access the progressbar from a different thread.
Take a look at this[^] for one solution.
If you search the CP articles for InvokeRequired, you will find several good articles on the subject.
Henry Minute
Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”
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Hello,
Everything is accessed from the main thread. InvokeRequired is false. I will look into other options.
Thanks for your reply.
Keith
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Here's[^] one of my articles that may be helpful.
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This looks promising. I will look into it and see how I can change it for my needs.
Thanks!
Keith
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hi
i have my C# program that work with sql-server 2008 Enterprise Edition
i have 40 users that connect to this database.
i dont close the connection.
how many open connection is recommended to leave ? or is it better to close connection ?
thank's in advance
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Close them - they are a finite resource. At present it works, but suppose they add another 10 users in six moths time. Will it work then? Or will you have to drop the top-priority task you are working on then and fit long nights into retro fixing your software? I know which I would prefer.
Do it right the first time: then you hopefully won't get any nasty shocks.
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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Always dispose the connection once the work is done. In case of ODP.Net, close and Dispose. Never leave a connection open.
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I close and open it again later -- why dispose?
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Hello,
I wrote my own installer in C#. It's all finished, except I'm having trouble with file type association, specifically file icons. I made my installer extract .ico embedded resource from its own .exe into the installation directory and set the registry key's DefaultIcon value to the icon file's path. (e.g C:\Program Files\Moonlite Map Studio\FileIcons\gx.ico,0), however in Windows Explorer only the .txt file icon shows up, so something must obviously be wrong.
What is the normal method to do it, and would I be able to do it programmatically?
Thanks,
Theo
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It seems Windows only likes icons if they're embedded in resource .dlls. How can I do this?
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No , windows use icon from dll , and exe files
I think the Structer of EXE .NET resource is different than other EXE
May be you must add icon your exe 16*16 , 32*32 , 48*48
any way use resource hacker for this Resource Hacker[^]
to check your exe and icon location ,
I know nothing , I know nothing ...
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Hi,
I don't have very specific answers, however:
1. I'm pretty sure it can all be done programmatically.
2. You will have to provide more than one resolution (all square, and multiples of 16). Windows will use different icons on different occasions (Windows Explorer, large icon/small icon; taskbar buttons; desktop shortcuts; etc); and it differs for different Windows editions (typically newer editions such as Vista/Win7 like to also have larger icons, up to 96*96).
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I need to get an image from the system clipboard (Clipboard.GetImage()) and serialize it to a file. The end goal would be to, at a later time, deserialize this image and put it back in the clipboard.
I can't figure out how to successfully serialize the image. I tried creating a serializeable class that contains an image object, but I get the exception
"The type System.Drawing.Bitmap was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically."
I tried using XmlInclude but am either doing it wrong or it does not resolve the problem.
Has someone done this before?
Darryl Borden
Principal IT Analyst
dborden@eprod.com
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Please avoid cross-posting questions across forums. You don't need to waste the time of one of the people trying to answer your question after somebody else has already answered it.
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