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You can buy a book on design patterns and go through them.
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Capturing a wealth of experience about the design of object-oriented software, four top-notch designers present a catalog of simple and succinct solutions to commonly occurring design problems. dofactoy[^] shows C# and VB.NET sample code of any GoF (Gang of Four: Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides) pattern.
Cheers,
Jani Giannoudis
Meerazo.com - Resource Sharing Made Easy | Co-founder
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Design patterns are a dime a dozen. Since you are a "beginner", then I would focus on the fundamentals first, and worry about patterns later.
Good luck.
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The code for that sample is available. Why not just look there?
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Hi
Thanks. I am not experinced in programming, was just told that it was a silverlight code that was hard to reuse as an ordinary VS code. But when looking into the details you are right.
Kind regards
Espen
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Excellent. I'm glad that has got you started.
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I am developing a web application using asp .net 2010 where I need to generate barcodes plus qrcodes dynamically and need to print it on different platform with different sizes.
How to achieve it? Which dll is useful for this? Whether microsoft have in build functionality for this or not? If yes then which DLL?
Winners don't do different thing they do things differently.
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There is no built in DLL in Windows or .Net - but there are several api's that can be downloaded (both free and paid) that will do this to varying levels and for various bar code types.
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Hi,
I have date data supplied as a string in the following format...
"Mon Sep 9 00:00:00 UTC 0100 2013".
Firstly, what is this format?
Secondly, how can I use C# to convert it and stire it in a DateTime variable?
I've tried...
DateTime dt = Convert.ToDateTime("Mon Sep 9 00:00:00 UTC 0100 2013"); but this blows up 
Many Thanks.
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Also tried...
DateTime dt = DateTime.ParseExact("Mon Sep 9 00:00:00 UTC 0100 2013", "ddd MMM dd HH:mm:ss K yyyy", CultureInfo.InvariantCulture);
Doesn't work either...
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See here[^]
it lists, d, D, f, F, g, G, M, m, O, o, R, r, S, t, T, u, U, y, Y as valid format strings, and below the table it says : Any other single character unknown specifier. Throws a run-time FormatException.
In my case it says: String was not recognized as a valid DateTime.
try to remove the K specification along with the 0100...
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Thanks for the reply.
I can't get it to work as a UTC. If I change it to UTC+ by adding the plus sign in to replace the space directly after the UTC on the fly then parse I can get it to work...
string strStart = "Mon Sep 9 00:00:00 UTC 0100 2013";
strStart = strStart.Replace("UTC ", "UTC+");
DateTime dtStart = DateTime.ParseExact(strStart, "ddd MMM d HH:mm:ss UTCzzzz yyyy", CultureInfo.InvariantCulture);
This works!
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So I've been stuck here for 1 week.
Everytime I had problem in SQL connection (ex. someone switch of server) my application will show exception message in a messagebox. I don't know when will the connection available except I keep trying to open the connection / execute a query.
So I create a wait form that will appear if connection is unavailable, keep trying to open the connection, and close itself when connection is available again.
To hide the freeze from user, I use backgroundworker.
This is the backgroundworker code
private void StartLoader(object sender, DoWorkEventArgs e)
{
for (int i = 1; i <= 10; i++)
{
if (this.par.sqSuccess)
{
break;
}
else
{
i -= 1;
}
System.Threading.Thread.Sleep(5000);
}
This is the backgroundworker progress changed event
this.cnn = new SqlConnection(this.par.Constr);
try
{
this.cnn.Open();
this.par.sqSuccess = true;
}
catch (Exception ex)
{
this.par.Exception = ex.Message;
}
finally
{
if (this.cnn != null) { this.cnn.Dispose(); }
}
if (this.par.sqSuccess) { this.Close(); }
After everything is complete, I tried to stop SQL service from services.msc, then I try to connect.
The wait form will appear and keep doing its job.
A few second after I try to connect, I start the service again and the wait form did close, success.
This is the problem, when I wait a little bit longer before I start the service again, the wait form still closed, but it takes a while.
After I check everything, it seems like the cnn.open() queue up and the longer I stop the service, the longer it takes for the wait form to close.
I searched google and try to add Connect Timeout=3; behind my connection string, as I'm sure my thread.sleep(5000) won't make them queue up, but still not working.
I need help to understand how this cnn.open works, why this is not working, what happen in this code that makes I got this problem.
While processing the cnn.open(), did my application execute the code below or wait for it?
Any help is appreciated, thank you. 
PS :
I use do while sqSuccess == false looping, I changed it to for just now and I know it makes no difference, so ignore it and the i-=1 too.
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You may like to try the OpenAsync[^] method.
Veni, vidi, abiit domum
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It uses System.Threading.Task.
Is it possible if I want to use it with backgroundworker?
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No idea, but I suggest you read the documentation, and try a few experiments.
Veni, vidi, abiit domum
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Oh ok ok.
There are no example of code inside but I will try googling.
Thank you very much.
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Oh cmon, I tried a lot of example and still not working.
I'm really really stuck here.
I'm not asking someone to do the code for me, at least tell me what is wrong in my code.
Please
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Midnight Ahri wrote: I tried a lot of example and still not working.
So you want us to guess a) what your code is doing, and b) what errors occur.
Midnight Ahri wrote: at least tell me what is wrong in my code.
As I said before, I have no idea.
However, re-reading your original message, it would seem much more sensible to post a message to the user when the connection fails. At least then someone can phone the help desk and alert them of the problem.
Veni, vidi, abiit domum
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Richard MacCutchan wrote: So you want us to guess a) what your code is doing, and b) what errors occur.
I've explained everything about my code.
I'm just asking about why the sql queue up.
By the way, thank you very much.
At least you teach me async and await technique.
And I appreciate that.
I'm not good at programming, so maybe I'll ask you something again.
See ya. 
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Why would you want to use BackgroundWorker when the Task is a better choice?
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Thank you very much, I'm new to task and just found it today.
But I'll keep searching.
After calling OpenAsync, State must return Connecting until the returned Task is completed. Then, if the connection was successful, State must return Open. If the connection fails, State must return Closed.
Sorry that english is not my first language and I'm not that good in programming.
So what I understand above is like this.
this.cnn.OpenASync();
if (this.cnn.State == ConnectionState.Connecting)
{
}
Then if it's busy, then I will return; instead of OpenASync() again.
if (this.cnn.State == ConnectionState.Closed)
{
}
And if it's closed, then I assume cnn failed and finished processing.
But it's not working.
It's ok, I'll search about task.
Thank you very much btw.
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