How to abort a thread waiting on a lock???

[mmx_nexus]

I have a requirement wherin i have a timer which raises events in a timespan of 5 milliseconds..and i have got a pice of code in the timercallback which basically retrieves data from the database,updates a dictionary and gives it back to the UI for processing.

Since the timeout is for 5 milliseconds,before finishing with the data loading part multiple threads seems to access the critical section(fetching data and updating dictionary) of the code.So,i did put a lock on the critical section and it works.But,my requirement is that i have to show the latest data on to the GUI,so i can ignore all the threads which are waiting on the lock till the lock aquired thread finishes processing.How should i tell all the threads which are waitng on a lock,not to wait on it but rather die itself??

[Mutant_Fruit]

private bool updating;
public void UpdateFromDatabase
{
    lock (whatever)
    {
        if (updating)
            return;

        updating = true;
    }
    
    GetDataFromDatabase();
    LoadDataIntoGrid();
    updating = false;
}

That'd do it fine.

However, updating every 5ms from a database is insanity. No-one can process data which updates every 5ms. You're requirement might be to show the latest possible data, but updating every 2 seconds would be just as fast as updating every 5ms when a human is trying to look at the data. Even every 5 seconds would probably be fine.