C#. Multithreading

I have two threads. First of them implements two methods, second only one. I need to synchronize threads this way: implementation of first method from first thread, implementation of method from second thread, implementation of second method from first thread. I tried to use barrier but it doesn't help:

bool complete = false;

// Start tasks
Task task_1 = factory.StartNew(() =>
{
    Console.WriteLine("1");
    Thread.MemoryBarrier();
    if (complete)
    {
        Console.WriteLine("3");
    }
});

Task task_2 = factory.StartNew(() =>
{
    //Thread.MemoryBarrier();    // Barrier 3
    Console.WriteLine("2");
    Thread.MemoryBarrier();    // Barrier 1
    complete = true;
    Thread.MemoryBarrier();
});
task_2.Wait();

How can I solve this?

Thank you very much!

Thank you for all your posts. I tried to use barrier class but the result is not which I need. I will try to explain my problem. I have few threads in which are called two or more methods:

 Barrier barrier = new Barrier(2); // 2 = #threads participating.
            bool complete = false;
            TaskFactory factory = Task.Factory;

            // Start tasks
            Task task_1 = factory.StartNew(() =>
            {
                process_1.Server("1 and 2");
                barrier.SignalAndWait(); // Wait for task 2 to catch up.
                barrier.SignalAndWait(); // Wait for task 2 to print "2" and set complete = true.

                if (complete)
                {
                    process_1.Server("1 and 3");
                }
            });
            Task task_6 = factory.StartNew(() =>
            {
                process_6.Server("6 and 4");
                process_6.Server("6 and 3");
            });
            Task task_2 = factory.StartNew(() =>
            {
                barrier.SignalAndWait(); // Wait for task 1 to print "1".
                process_2.Client("1 and 2");
                complete = true;
                barrier.SignalAndWait(); // Wait for task 1 to read complete as true.

                process_2.Server("2 and 5");
                process_2.Server("2 and 3");
            });
            Task task_4 = factory.StartNew(() =>
            {
                process_4.Client("6 and 4");
                process_4.Server("4 and 7");
                process_4.Server("4 and 3");
            });
            Task task_5 = factory.StartNew(() =>
            {
                process_5.Client("2 and 5");
                process_5.Server("5 and 3");
            });
            Task task_7 = factory.StartNew(() =>
            {
                process_7.Client("4 and 7");
                process_7.Server("7 and 3");
            });
            Task task_3 = factory.StartNew(() =>
            {
                process_3.Client("1 and 3");
                process_3.Client("2 and 3");
                process_3.Client("4 and 3");
                process_3.Client("5 and 3");
                process_3.Client("6 and 3");
                process_3.Client("7 and 3");
            });

            task_3.Wait();

I need to ensure consequence between calling methods from different threads for example: process_1.Server("1 and 2"); and process_2.Client("1 and 2");. Calling Client method before Server is not acceptable. All the dependencies: {process_1.Server("1 and 2"); process_2.Client("1 and 2");}, {process_2.Server("2 and 5"); process_5.Client("2 and 5");}, {process_6.Server("6 and 4"); process_4.Client("6 and 4");}, {process_4.Server("4 and 7"); process_7.Client("4 and 7");}, {process_1.Server("1 and 3"); process_3.Client("1 and 3");}, {process_2.Server("2 and 3"); process_3.Client("2 and 3");}, {process_4.Server("4 and 3"); process_3.Client("4 and 3");}, {process_5.Server("5 and 3"); process_3.Client("5 and 3");}, {process_6.Server("6 and 3"); process_3.Client("6 and 3");}, {process_7.Server("7 and 3"); process_3.Client("7 and 3");}.

Between elemets {...} and {...} there are no dependecies. So it is possible to execute {process_6.Server("6 and 3"); process_3.Client("6 and 3");}, {process_7.Server("7 and 3"); process_3.Client("7 and 3");} or vice versa {process_7.Server("7 and 3"); process_3.Client("7 and 3");}, {process_6.Server("6 and 3"); process_3.Client("6 and 3");}. There are dependencies between elements into {...} which I wrote. Can you help me to solve this problem? I can not figure out how to implement this. Thank you very much!