How to create a Request Specific Thread Safe Static int Counter?

Question

In one of my server application I have a class that look like,

class A
{
 static int _value = 0;
 void DoSomething()
 {
 // a request start here
 _value = 0;
 _value++;
 // a request end here
 }
 // This method can be called many time during request
 void SomeAsyncMethods()
 {
 _value++;
 }
}

The problem is SomeAsyncMethods is async. Can be called many times. What I need when a request start set _value = 0 and then asynchrosnously increment this. After end of request I need the total. But the problem is that another request at the same time can access the class.

Answer 1

use

System.Threading.Interlocked.Increment( ref _value );

instead of

_value++;

Interlocked.Increment

If multiple requests share this class and each one should get its own counter you need a non static counter that you pass to all threads working on this request.

Like this

class A
{
 void DoSomething()
 {
 // a request start here
 RequestData data = new RequestData();
 request.IncrementValue();
 // a request end here
 }
 // This method can be called many time during request
 void SomeAsyncMethods( RequestData request )
 {
 request.IncrementValue();
 }
}
class RequestData
{
 int _value = 0;
 public void IncrementValue()
 {
 System.Threading.Interlocked.Increment( ref _value );
 }
}