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Right, it should mention loops.
I'd also say not to throw away a perfectly good StringBuilder just to create another; reuse it if possible.
One thing I've seen done all too often is something like:
for each row in a table
instantiate a StringBuilder (with the default length of 16 no less!)
for each column
Append a comma (possibly with a test first)
Append the value
write it somewhere with ToString()
A better pattern is:
instantiate a StringBuilder (ideally with some estimate of how much space is required by the longest record)
for each row in a table
set the StringBuilder's Length to 0
for each column
AppendFormat the value and a comma
write it somewhere with ToString ( 0 , Length-1 ) to eliminate the extraneous comma
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First, assuming that the compiler understands your program no matter how poorly you write it, it is more important that people understand it. From that flows:
Be consistent -- especially in formatting.
Be verbose -- "saving keystrokes" is a bad thing in the long run.
Too many comments is better than too few -- at least they're easier to delete than add.
Avoid premature optimization.
Expect that the developer who might come after you will come after you.
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hi guys
i just want a program that can connect to other program on other computer and also get connected , and i'll make it clear .
i want a program that send and recive data .
like a server and client in one program .
like a chat program .
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Then write it! We're not going to do the work for you.
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okay then .
the code that im using in the server side is like this
Thread thr;
Socket Soc = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipend = new IPEndPoint(IPAddress.Any, 8000);
private void buttonX1_Click(object sender, EventArgs e)
{
thr = new Thread(Listen);
thr.Start();
}
void Listen()
{
Soc.Bind(ipend);
Soc.Listen(10);
byte[] data = new byte[500];
while (true)
{
Socket client = Soc.Accept();
client.Receive(data);
sth = Encoding.ASCII.GetString(data);
client.Shutdown(SocketShutdown.Both);
client.Close();
}
}
and the client side is like this
Socket soc = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipend = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 8000);
soc.Connect(ipend);
string input = textBoxX1.Text;
byte[] data = new byte[500];
data = Encoding.ASCII.GetBytes(input);
soc.Send(data);
string sth = "";
sth = Encoding.ASCII.GetString(data1);
textBoxX2.Text = sth;
i think you know what im done , but this code is doing so far i get of it . i click the listen button in the server side and the server w'll listen to the line so after i fill the textbox in the client form and click the send button it'll send the data and i can get the data perfectly in the server side
but i need two more things to be done , i want the server do the same thing that the client do that's mean send data to client . and i want the client do the same thing as server that's mean get the data from the server .
i hope you get the idea .
both of them do both sending and receiving at the same time .
how that should be possible ?
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OK, the Socket object you created has a bunch of Send methods. So, you receive your message from the client, process it, then sned a response back to the client just like the client code does.
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i dont think is as easy as you said . when im listening to the line by the server computer
how should i respond it ? i know one thing that if the client send the server any message , the server can send any message right a way back to the client after it gets the message from the client . but i dont want to send message right back to the client like this way , i want to have a sperate button on the server that if i clicked it the message w'll send to the client and also recieve the message from the client too .
i dont know , if you get it or not.
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Then you'll have to have two threads, one listening and one writing. No, I don't have any examples because I've never heard of anyone doing this. Usually, it's one thread that listens, responds, listens, reponds, ...
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Sounds fun - hope you enjoy coding it as much as I would!
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the code that im using in the server side is like this
Thread thr;
Socket Soc = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipend = new IPEndPoint(IPAddress.Any, 8000);
private void buttonX1_Click(object sender, EventArgs e)
{
thr = new Thread(Listen);
thr.Start();
}
void Listen()
{
Soc.Bind(ipend);
Soc.Listen(10);
byte[] data = new byte[500];
while (true)
{
Socket client = Soc.Accept();
client.Receive(data);
sth = Encoding.ASCII.GetString(data);
client.Shutdown(SocketShutdown.Both);
client.Close();
}
}
and the client side is like this
Socket soc = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipend = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 8000);
soc.Connect(ipend);
string input = textBoxX1.Text;
byte[] data = new byte[500];
data = Encoding.ASCII.GetBytes(input);
soc.Send(data);
string sth = "";
sth = Encoding.ASCII.GetString(data1);
textBoxX2.Text = sth;
i think you know what im done. i click the listen button in the server side and the server w'll listen to the line so after i fill the textbox in the client form and click the send button it'll send the data and i can get the data perfectly in the server side
but i need two more things to be done , i want the server do the same thing that the client do that's mean send data to client . and i want the client do the same thing as server that's mean get the data from the server .
i hope you get the idea .
both of them do both sending and receiving at the same time .
how that should be possible ?
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You could look in MSDN[^] or just Google for "C# sockets", to get all the information you need.
One of these days I'm going to think of a really clever signature.
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This sounds like a classic homework question. Before you start coding it, you need to analyse the problem that you are facing (this doesn't just apply to homework, any program that you write should have some degree of thought put into it beforehand).
When you analyse the problem, based on the level of detail you've currently supplied, it really breaks down into three parts. The first part is that you want to have code that can send data. The second part is that you want to have code that can receive data. The third part (it's kind of implicit here), is that you want your send and receive code to be performed on threads as your problem reads like the application must be able to do both things at the same time; I could be wrong about this - only you know the requirements here.
Some things you need to consider - how is the program terminated? What happens to the sending code if the program that is receiving data terminates unexpectedly? What happens to the sending application if the receiving application terminates (how does it know that it's terminated - you don't want to attempt to send if there's nothing at the other end)? What if the receiving end outage is only temporary? Do you attempt to resend data?
As you can see, there's a lot of thinking you need to do beforehand. You really need to consider what the application "infrastructure" is, taking things such as resiliency into account.
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The way you formulated it (that is, without going through a server), you'll probably have to traverse NAT at some point.
Just something to keep in mind and be prepared for.
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Hey all,
I am a bit disappointed by myself to come up with that question, but hey! there are some regex cracks here that can easily answer this question and maybe deepen my understanding. I really tried to figure out the best regex for my problem - but I am new to programming and regex' still seem to make my head explode.
Here's the string I've got:
Directory\Subdirectory\Subdir\Subsubdir\sub_sub_subv009\filename_with_lots_of_ABC123.txt
using this regex:
(?<=_)[a-zA-z0-9]*(?=.txt$)
I get:
of_ABC123
Close call, but what I need is just ABC123 - this are all characters as a string between the LAST '_' and ".txt"
Additionally, I did this in Expresso (did not use the designer but did a lot of test runs to see if my regex matches) - will this be the regex to be used in C#?
I really appreciate any hint to solve my last problem,
Best
Dennis
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First of all, if you have a regex question, there is a regular expression forum that should be used. Secondly, not every string manipulation requires a regex - a much simpler way would be to use string.LastIndexOf for the _ and IndexOf the . character and then just extract the substring from it.
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Here is an example of solution using both Regex and string class methods. In Regex I use a group with "FileCode" name to get result.
As Pete said not all cases require using of Regex. And in this case I think would be better to use string methods (alternative variant).
const string pattern = @"_(?<FileCode>([^_][a-zA-Z0-9])+)\.txt$";
const string text = @"Directory\Subdirectory\Subdir\Subsubdir\sub_sub_subv009\filename_with_lots_of_ABC123.txt";
var groupFileCode = Regex.Match(text, pattern);
Console.WriteLine(groupFileCode.Groups["FileCode"].Value);
int lastUnderscoreIndex = text.LastIndexOf('_');
int lastPointIndex = text.LastIndexOf('.');
Console.WriteLine(text.Substring(lastUnderscoreIndex + 1, lastPointIndex - lastUnderscoreIndex - 1));
Regards, savbace
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Your range is [a-zA-z0-9] - notice the second "z" is lower case, and as "_" falls between uppercase A and lowercase z it is included in your match.
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Thank you so much! I have overseen this. So I have at last understood a little bit of regex and did it right. Thank you also for the other answers, especially the C# code examples. I will try them tomorrow!
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for reference, my regex links:
learn:
http://www.guistuff.com/articles/regexp_full_1.html
http://net.tutsplus.com/tutorials/javascript-ajax/you-dont-know-anything-about-regular-expressions/
online testing:
http://refiddle.com/
http://www.gethifi.com/tools/regex
http://gskinner.com/RegExr/
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I'd likely use System.IO.Path.GetFileNameWithoutExtension to narrow it down first, then use LastIndexOf and Substring as others have suggested.
Were I to use a Regex, I'd likely use _(?'Name'[^_\.]+)\.
I prefer to use named groups to capture what I want.
You may want to look at the RightToLeft option as well; very handy for getting stuff that follows other stuff.
Oh, and I use this handy tool: RegexTester[^]
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Hi,
I am in the process of writing a c# application.
There is one stored proc(sql server 2005), which is supposed to return two output values, and a resultset selection from one table.
I am able to select out the output values from stored proc(by defining the parameters with output direction), how can I select out the resultset from that one table?
Or should I write this as another stored proc?
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Forgive me, but I'm making a few assumptions here in regards to your question...
CREATE PROCEDURE dbo.Foo
@StateCode AS CHAR(2),
@OutVariable1 AS INT OUTPUT,
@OutVariable2 AS INT OUTPUT
AS
BEGIN
SET @OutVariable1 = 100
SET @OutVariable2 = 150
SELECT * FROM dbo.Persons WHERE State = @StateCode
END
string stateCode = "AL";
int outValue1 = 0;
int outValue2 = 0;
using (SqlConnection = new SqlConnection(connectionString)) {
using (SqlCommand cmd = new SqlCommand("dbo.Foo") ) {
cmd.CommandType = CommandType.StoredProcedure;
cmd.Paramaters.Add("@StateCode", SqlDbType.Char, 2) = stateCode;
SqlParameter outValue1Param = cmd.Parameters.Add("@OutVariable1", SqlDbType.Int);
SqlParameter outValue2Param = cmd.Parameters.Add("@OutVariable2", SqlDbType.Int);
using (DataReader dr = cmd.ExecuteReader()) {
while ( dr.Read() ) {
}
}
outValue1 = (int) outValue1Param.Value;
outValue2 = (int) outValue2Param.Value;
}
}
I hope that helps.
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Thanks so much! that looks good.
I am getting data for the while loop but in case of the output parameters, it keeps coming back with error - object reference is not set to an instance of an object. When I try to debug the program, these values are being set as null.
the stored proc does return values.
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Hi,
I appears when I use ExecuteNonQuery to get the output parameter values, it works.
But when I use ExecuteReader, then it has NULL values for the parameters.
any thoughts?
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