Question

I have a an application that requires threading in most cases. Most of the time I will encounter errors or wrong values because the object was updated prior to its execution for each thread.

Do you have any suggestion how to make objects be thread safe and making sure that objects have the correct for each thread? Should I make my variables static?

Answer 1

Look into using the lock statement for any resources that you need to make thread safe.

http://msdn.microsoft.com/en-us/library/c5kehkcz.aspx

class Account
{
    decimal balance;
    private Object thisLock = new Object();

    public void Withdraw(decimal amount)
    {
        lock (thisLock)
        {
            if (amount > balance)
            {
                throw new Exception("Insufficient funds");
            }
            balance -= amount;
        }
    }
}

This would be my first step. Also you can look into the Monitor class.

http://msdn.microsoft.com/en-us/library/system.threading.monitor.aspx

These are the two basic ways that you can protect your resources during concurrent operations. There are many other ways such as mutexes, sempahores, conditional read/write locks,etc.