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I would go for a single SQL statement that fills a single table with all required information, it would look somewhat like this:
select NAME_Product from Product where Product.ID_Product IN ( '"+str1+"' ", '"+str2+"' ", '"+str3+"' )
and you may want to append GROUP BY Product.ID_Product
So you would need:
- a loop to build the one SQL statement
- the execution of that SQL stm resulting in one DataTable
- a loop to tell your chart where to find all the data series
Luc Pattyn [My Articles] Nil Volentibus Arduum
Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.
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Luc Pattyn [My Articles] Nil Volentibus Arduum
Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.
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How can we write the long source of a program in
2 or 3 files and relate them together at build time.
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I rather think he has five source-files (.cs) that should be linked to a single executable. The IDE does that for us
Bastard Programmer from Hell 
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The question (as with so many) is somewhat open to interpretation. 
Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman
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Yes, but the wording "two or three files" are a give-away.
..with everybody recommending on how to distribute classes over multiple files 
Bastard Programmer from Hell 
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Which is why I made the suggestion that I did.
Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman
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better way is to ask for more information about the question.!!!
@faraz34 : what exactly you would like to achieve ? whats your problem ?
thanks
-Amit.
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Not at all; I gave an answer which may be the right one. If not then OP can respond with more details.
Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman
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the ways of an MVP, you should treat with the greatest respect!
Luc Pattyn [My Articles] Nil Volentibus Arduum
Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.
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If you referring to writing classes with an extensive amount of code. Then I'd suggest you use the "partial" key word. That way you can spread your class over separate files. In each file you just call the full declaration of the class but with the partial key word. Eg;
public partial class Employee
{
public void DoWork()
{
}
}
public partial class Employee
{
public void GoToLunch()
{
}
}
http://msdn.microsoft.com/en-us/library/wa80x488%28v=vs.80%29.aspx[^]
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faraz34 wrote: How can we write the long source of a program in
2 or 3 files and relate them together at build time.
1. Design your application so that you can break the functionality into classes. Classes normally are rather small. This step has nothing to do with actually writing code.
2. Implement each class in a different file.
3. In C# you put all of the classes in a project which is then managed via a solution.
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jschell wrote: 3. In C# you put all of the classes in a project which is then managed via a
solution.
You mean "in Visual Studio"; C# neither knows nor cares about projects and solutions.
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csc /out:My.exe *.cs
Will compile all .cs files within that folder into My.exe. Snippet taken from MSDN[^].
Bastard Programmer from Hell 
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Yes, but I use /recurse:"*.cs"
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In addition to using *.cs you can also put the specific files:
csc MyFirstClass.cs MySecondClass.cs etc.cs
The name of the first will be used to name the output (i.e. MyFirstClass.exe in this case) unless you specify a /out: target.
IDEs generally hide this away from you – are you writing code in a text editor? You don't normally need to do that, as there are good free IDEs available for .Net.
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Hi I would like to use argument in ThreadStart Delegate but I have problem with syntax. here the code example
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
namespace mtquestion
{
class Program
{
static void Main(string[] args)
{
Thread T1 = new Thread(new ThreadStart(C(15,25)));
Thread T2 = new Thread(new ThreadStart(C(15, 29)));
Thread T3 = new Thread(new ThreadStart(C(18, 25)));
T1.Start();
T2.Start();
T3.Start();
object locker = new object();
lock (locker)
T1.Join();
T2.Join();
T3.Join();
lock (locker)
Console.Write("c");
}
public static void C(double a, double b) { Console.WriteLine(a*b);}
}
}
the syntax
Thread T1 = new Thread(new ThreadStart(C(15,25)));
return the following error"method name expected"
How can I pass arguments?
Thanks for your time
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In order to pass arguments, you need to look at using a ParametrizedThreadStart instead:
Thread T1 = new Thread(new ParameterizedThreadStart(Y));
T1.Start(42);
...
public static void Y(object i) { Console.WriteLine("Hello: "+ i); }
Ideological Purity is no substitute for being able to stick your thumb down a pipe to stop the water
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Thanks a lot for answer
Just last help: suppose I need many parameters let's say a double, a DateTime[] and a Dictionary<>,
How can I manage only using the parameter (object i).
To be more clear, I have something like:
public static void Y(double a, DateTime[] myDates, Dictionary<string,double> myDic)
I suppose there is a workaround to fit all in object and using casting.
thanks for your time
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Personally, I would create a TaskParameter class with the required properties and pass over a single instance to the task. If nothing else, it gives a nice object for locking should that prove necessary later.
Ideological Purity is no substitute for being able to stick your thumb down a pipe to stop the water
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Hi,
you don't need the locks you have:
1. Thread.Join() is thread-safe by itself, you adding locks does not help a bit. This is not documented, however it should be obvious as the thread executing the join is doing nothing but wait.
2. Console output is thread-safe also, otherwise Console output would most always be garbled as most apps have several threads. This too is not documented AFAIK.
Locks do make sense when you have one or more methods that:
- want access to the same data;
- AND can be executing at the same time, which implies by different threads.
And even then, for atomic operations, you still wouldn't need a lock (but you may need the volatile keyword). Atomic here means the data operation is performed by a single assembler instruction, e.g. a 32-bit int load or store; a set of atomic items (e.g. a struct) is itself not atomic, so if two ints need to represent a consistent state, then you also would need a lock. When in doubt about atomocity, be safe and use a lock.
And lock objects must be accessible by all methods involved, so a local variable can not serve that purpose. It should be a class member. And for safety, it shouldn't be public: it should be accessible only to the objects that need access.
Luc Pattyn [My Articles] Nil Volentibus Arduum
Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.
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Thank you for your very good answer. My question was incomplete.
Basically I also need a thread called "total" that sum the "y" calculated in C.
For do that I have 2 problem:
-> total has to wait each C to finish
-> total has to get data from each C (how passing data?)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
namespace mtquestion
{
class Program
{
static void Main(string[] args)
{
Thread T1 = new Thread(new ParameterizedThreadStart(C));
Thread T2 = new Thread(new ParameterizedThreadStart(C));
Thread T3 = new Thread(new ParameterizedThreadStart(C));
T1.Start(15000000);
T2.Start(25000000);
T3.Start(60000);
T1.Join();
T2.Join();
T3.Join();
Console.WriteLine("All 3 done");
}
public static void C(object i)
{
double y = 0.0;
for (int j = 1; j<(int) i; j++)
{
y += Math.Log(Math.Exp(0.06)) * Math.Log(Math.Exp(0.06)) / Math.Log(Math.Exp(0.06)) * Math.Log(Math.Exp(0.06));
}
Console.WriteLine(i);
}
public static void Total(object j)
{
C(..) when conclueded
}
}
}
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There are dozens of ways to get a total result from the work of several threads. I'll list just a few:
1.
have a single variable "double total" accessible by all thread methods involved; now let each threaded method add its result to it. This is a situation where you need a lock (you shouldn't allow multiple threads to read and write the total value at exactly the same time).
2.
have a single queue accessible by all threads; each threads pushes its result to the queue; when all is done (after the join point), the main thread pops everything from the queue and calculates the sum. As the typical queue isn't thread-safe, here too you'll need a lock.
2bis.
like 2, but using some synchronization means to have yet another thread calculate total. See e.g. ManualResetEvent type.
3.
much simpler: have a little job class, which is intended to hold all the input parameters and the results of each thread. Instantiate one instance for each job/thread, have the thread get its values from there, and store its results in there as well. Also maintain a collection of these jobs, so the totalizer can enumerate the jobs and accumulate their results.
4.
often my preference: like #3, however put the actual job code also inside the job class, which means all threading code is encapsulated there too. Here is an example:
class Job {
private int parm1;
private int parm2;
public int Result;
private Thread thread;
public Job(int parm1, int parm2) {
this.parm1=parm1;
this.parm2=parm2;
}
public void Run() {
thread=new Thread(new ThreadStart(runner));
thread.Start();
}
public void Join() {
thread.Join();
}
private void runner() {
Result=parm1+parm2;
}
}
class Test {
public static Main() {
List<Job> jobs=new List<Job>();
for(int i=0; i<10; i++) {
Job job=new Job(3*i, i+12);
jobs.Add(job);
job.Run();
}
foreach(Job job in jobs) job.Join();
int total=0;
foreach(Job job in jobs) total+=job.Result;
}
}
I suggest you read up on all the classes/types I mentioned, and better yet, read about threading in your C# book.
Luc Pattyn [My Articles] Nil Volentibus Arduum
Fed up by FireFox memory leaks I switched to Opera and now CP doesn't perform its paste magic, so links will not be offered. Sorry.
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