How to pass parameters to thread by reference in c#?

Question

I have to pass multiple parameters to a thread. I have wrapped them into a class object. In which one variable (double array) i want pass it as reference (I am expecting the result in this variable). How does it possible?

class param
{
   int offset = 0;
   double[] v = null;
}
param p = new param();
p.v = new double[100]; // I want to pass this(v) variable by reference
p.offset = 50;

....
thread1.Start(p);

Answer 1

Description

There are many solutions. One is, you can use ParameterizedThreadStart for that.

Sample

param p = new param();

// start the thread, and pass in your variable   
Thread th = new Thread(new ParameterizedThreadStart(MyThreadMethod));
th.Start(p);

public void MyThreadMethod(object o)
{
    // o is your param
    param pv = (param)o;
}

More Information

• MSDN - ParameterizedThreadStart Delegate

Answer 2

You could also just pass the param variable when you declare the thread:

static void Main()
{
  param p = new param();
  p.v = new double[100]; // I want to pass this(v) variable as reference
  p.offset = 50;
  Thread t = new Thread ( () => MyThreadMethod(p) );
  t.Start();
}

static void MyThreadMethod(param p) 
{
  //do something with p
  Console.WriteLine(p.v.Length);
  Console.WriteLine(p.offset);
}

Check out Joseph Albahari's free e-book on threading here.

I like this approach since you don't need to deal with other objects -- just create a lambda in your Thread constructor and you're off to the races.

Hope this helps!