its regarding Multi-threading

Mystic_

i while doing work came up to introducing multi threading in my application but the problem in my case is that the signature of function or functions i want to execute in the thread doesnot match that of delegate "ThreadStart". those parameter that i pass to my functions r very important i have already spend alots of time finalizing them. so anyway out?? i will be very thankful for any kind help.

Ennis Ray Lynch Jr

Have your method set members within your class and then use thread start within your method with the special parameters. Keep in mind you will have to be very careful of synchronisity when doing this but that is the method I use. (sometimes) A man said to the universe: "Sir I exist!" "However," replied the Universe, "The fact has not created in me A sense of obligation." -- Stephen Crane

Mystic_

its like one class and i use local variables of a method to pass values to these method(those which r passed to ThreadStart delegate). to put it simple and straight. its a switch case statement. in one statement i want to initiate one method and in other case statement i want to intiate an other method. so i have declared a golab Thread instance and initialize it in every case statement. main problem is with the signature of my methods. every time i run the programe, an error appears say that " Method 'Download(string, Testing.Form1.Data, string, string)' does not match delegate 'void System.Threading.WaitCallback(object)'"

Judah Gabriel Himango

Are you using C# 2? If so, you can use anonymous delegates to do this:

void Foo()
{
int val = 5;
string text = "blah";

// Use an anonymous method to pass the locals to the function.
ThreadPool.QueueUserWorkItem(delegate
{
    OnAnotherThread(val, text);
});

}

void OnAnotherThread(int i, string s)
{
MessageBox.Show(s);
}

Another way--the way that the C# 2 compiler implements it under the hood--is to create a class that stores the variables you want to pass to the function, then create a function in that class whose signatures matches WaitCallback. Here's an example:

void Foo()
{
int val = 5;
string text = "blah";

HolderClass holder = new Holder(val, text);
ThreadPool.QueueUserWorkItem(holder.OnAnotherThread);

}

class HolderClass
{
private int value;
private string text;

 public HolderClass(int value, string text)
 {
     this.value = value;
     this.text = text;
 }

 public void OnAnotherThread(object state)
 {
      MessageBox.Show(this.text);
 }

}

Tech, life, family, faith: Give me a visit. I'm currently blogging about: Messianic Instrumentals (with audio) The apostle Paul, modernly speaking: Epistles of Paul Judah Himango

Mystic_

iam using VS 2003 and SDK V 1.1 its not supported in my version

Mystic_

it would be a mess if i do it with global variables. it would be my last resort. if it ever is.

Jun Du

You don't have to use global data. Instaed, you can create a wrapper class which contains your thread function and all other related methods and data members. The only constraint is that all of the methods and data members should be static. The following C++ code snippets are extracted from my CP article http://www.codeproject.com/useritems/xlogoff.asp[^]. My thread function processes lots of data within the class. One thing to note is that I used mutex to protect the data accessed by more than one thread. Here is the OnStart() in my Windows service code, which simply starts a thread:

void OnStart(String* args[])
{
// Start the communication thread
Thread *oThread = new Thread(new ThreadStart(0, &XLogoffThread::ThreadProc));
oThread->Start();

// some code omitted...

}

Here is the thread class which contains a thread function as the delegate function to ThreadStart and all other methods and data:

public __gc class XLogoffThread
{
private: static String* prevSession;
private: static String* DATA_FILE = S"session.dat";
private: static ArrayList* baseline = new ArrayList;
public: static Mutex * mut = new Mutex();
private: static SnippetsCPU::ProcessAsUser *cpau = new SnippetsCPU::ProcessAsUser();
// The ThreadProc method is called when the thread starts.

public: static void ThreadProc()
{
try
{
// Create the session data file
if ( !File::Exists(DATA_FILE) )
{
File::Create(DATA_FILE);
}

  // Set the server to listen on port 30000
  Int32 port = 30000;
  IPAddress\* localAddr = IPAddress::Parse(S"127.0.0.1");
  TcpListener\* server = new TcpListener(localAddr, port);
  Byte bytes\[\] = new Byte\[128\];

  // Start listening for connections
  server->Start();

  // Enter the listening loop.
  while (true) 
  {
    // Perform a blocking call to accept requests.
    TcpClient\* client = server->AcceptTcpClient();            
    String\* data = 0;

// Get a stream for reading and writing
NetworkStream\* stream = client->GetStream();

// Loop to receive all the data sent by the client.
do
{
  // Read bytes
  Int32 i = stream->Read(bytes, 0, bytes->Length);					 
  // Convert to an ASCII string.
  data = Text::Encoding::ASCII->GetStr

Mystic_

thanx alot buddy. i will try it out. but one thing about ur code of class XLogoffThread. it never use those static properties in the ThreadProc(). so whats the use of those fields. i asked because thats the concept iam going to implement.

Jun Du

ProcessCmd(data) and its delegates use these data. Most of the code has been omitted in the post. You might want to grab the complete code following the link in that post. Best, Jun

Gavin Roberts

why don't you just use a delegate?! public delegate void Name(object param1, object param2); private void MyMethod(object param1, object param2) { // do what you need. } then call Name n = new Name(MyMethod); // control being a listView or form etc. control.Invoke(n, new object[] { "test", "test2" });

Judah Gabriel Himango

Who said anything about globals? There are no globals in C#; everything belongs to a class. Use the second example I gave, it would work fine for you.

Tech, life, family, faith: Give me a visit. I'm currently blogging about: Messianic Instrumentals (with audio) The apostle Paul, modernly speaking: Epistles of Paul Judah Himango

Mystic_

i meant golab in a class. its bit vague term but i use it for public members of a class.

Mystic_

yeh but annoymus delegate wont work with .Net 1.1. i have that one. there got to be other solutions for this version as well.

Mystic_

i got ur point and i have already transformed my code in way u said. its doing great. thanx buddy