Passing in a string to a thread I am about to start? [C# 2002]

I am trying to accomplish something like this:

Code:

---

{
  string sType ="Update";
  Thread th1 = new Thread (new ThreadStart(Operation1(sType)));
  th1.Start();
}

private void Operaton1(string sType)
{
  if (sType == "Update")
  {
  }
  else
  {
  }
}

---

Obviouslly this doesn't work and returns and error message as follows:
Method name expected

It works fine if my "Operation1" has no parameters but I somehow need to pass the information from "sType" into the Thread itself...
How could I accomplish passing a STRING into a THREAD I am about to start?

Any help would be greatly appreciated.
Thanks,

Hi there,
I'm certainly no expert in threading, but I read up a little bit and using your version of the framework you can consider storing your variable in an instance of a class. So perhaps something like this:

c# Code:

// My form.
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 
        // New instance of my other class.
        private void button1_Click(object sender, EventArgs e)
        {
            string str = "Update";
            MyOperations op = new MyOperations(str);
            new Thread(new ThreadStart(op.Operation1)).Start();
        }
    }
 
    // My other class.
    public class MyOperations
    {
        string _str;
 
        public MyOperations (string str)
        {
            this._str = str;
        }
 
        public void Operation1()
        {
            if (_str == "Update")
            {
                MessageBox.Show("Update.");
            }
            else
            {
                MessageBox.Show("No update.");
            }
        }
    }

I did find many sites that spoke about this topic in my search with much more information. Give Google a go and I'm sure you'll find plenty. I hope this little gets you started. :)

Thats a great idea - and while trying to implement it I ran into a single roadblock - Operation1 uses functions part of the class that is spawning the thread - if I pass in a class.function as opposed to a local function I loose scope of these functions and can no longer launch them (from what I can see). For example ... using your code ...

Code:

---

// My form.
public partial class Form1 : Form
{
        public Form1()
        {
                InitializeComponent();
        }
       
        // New instance of my other class.
        private void button1_Click(object sender, EventArgs e)
        {
                string str = "Update";
                MyOperations op = new MyOperations(str);
                new Thread(new ThreadStart(op.Operation1)).Start();
        }

        private delegate void DoTheWorkDelegate
        private void DoTheWork(string sStuff)
        {
                // DoTheWork stuff
                // This can be called by a thread using “DoTheWorkDelegate”
        }
}

// My other class.
public class MyOperations
{
        string _str;
        public MyOperations (string str)
        {
                this._str = str;
        }
       
        public void Operation1()
        {
                if (_str == "Update")
                {
                        DoTheWork(“update”);
                }
                else
                {
                        DoTheWork(“not update”);
                }
        }
}

---

So doing it that way I get errors because "DoTheWork" is not defined in the new class "MyOperations" - any clue how to solve this aside from passing the "this" into the "MyOperations" class also and doing something like this.DoTheWork? (as I am not sure how threadsafe that kind of request would be).

Thanks,

Heres a simple example of passing a string to a thread:

C# Code:

private void Form1_Load(object sender, EventArgs e)
        {
            System.Threading.Thread thr1 = new System.Threading.Thread(DoWork);
            thr1.Start("Hello");
 
        }
 
        private void DoWork(object obj)
        {
            string Message = Convert.ToString(obj);
            MessageBox.Show(Message);
        }

Quote:

---

Originally Posted by Atheist

Heres a simple example of passing a string to a thread:

C# Code:

private void Form1_Load(object sender, EventArgs e)
        {
            System.Threading.Thread thr1 = new System.Threading.Thread(DoWork);
            thr1.Start("Hello");
 
        }
 
        private void DoWork(object obj)
        {
            string Message = Convert.ToString(obj);
            MessageBox.Show(Message);
        }

---

Wow, that was quite easy. I can't believe that in all of sites that I looked on regarding passing a parameter to a new thread, that I didn't see that. All of them mentioned something with a class.

Is this also available in 1.1? I'm not sure how the documentation on MSDN is exactly for 1.1, but they don't show an Overload for this method.

If you want to be able to execute a method of an object you have no reference to then you need to pass a delegate. The very reason that delegates exist is to enable executing methods without references to their owners. Create a DoTheWorkDelegate instance and pass it to your MyOperations object, from which it can be invoked.

jmcilhinney: How do you pass in a delegate to a thread?

As it stands the solution I found was to pass in the "this" pointer to the thread so that I can access all the required functions - and in the spawning class I created delegates for each function based on the Invoke requirements. I did a quick test and it looks like, when in my thread, if I do something like fMain.DoSomething the thread will go to the calling class and be Invoked and then run the function.

Is this also a correct and threadsafe way to do it?