C# – 2 digit number in c#

A need some help, I have a TextBlock that contains a string like this 00:00:00 And I want to create a timer that will count every second e.g.00:00:01 , 00:00:02 etc

So the stupid thing that I do is to take the value of the text box

string[] times = myTextbox.Text.Split(':');
int hours = Int32.Parse(times[0]);
int minutes = Int32.Parse(times[1]);
int seconds = Int32.Parse(times[2]);

Then I increase the right variable and finally I join them again and put them back in the textblock, BUT now my counter is like this: 0:0:1, 0:0:2, …

I know the problem, its very logical but my question is how can I solve it 🙂

Thank you very much.

Best Answer

string displayString = String.Format("{0:00}:{1:00}:{2:00}", 
 hours, minutes, seconds);

The part after the : is a format description. 00 means always use at least two positions and show an empty position as 0.

Related Solutions

C# – .NET String.Format() to add commas in thousands place for a number

String.Format("{0:n}", 1234);  // Output: 1,234.00
String.Format("{0:n0}", 9876); // No digits after the decimal point. Output: 9,876

C# – Random number generator only generating one random number

Every time you do new Random() it is initialized using the clock. This means that in a tight loop you get the same value lots of times. You should keep a single Random instance and keep using Next on the same instance.

//Function to get a random number 
private static readonly Random random = new Random(); 
private static readonly object syncLock = new object(); 
public static int RandomNumber(int min, int max)
{
    lock(syncLock) { // synchronize
        return random.Next(min, max);
    }
}

Edit (see comments): why do we need a lock here?

Basically, Next is going to change the internal state of the Random instance. If we do that at the same time from multiple threads, you could argue "we've just made the outcome even more random", but what we are actually doing is potentially breaking the internal implementation, and we could also start getting the same numbers from different threads, which might be a problem - and might not. The guarantee of what happens internally is the bigger issue, though; since Random does not make any guarantees of thread-safety. Thus there are two valid approaches:

Synchronize so that we don't access it at the same time from different threads
Use different Random instances per thread

Either can be fine; but mutexing a single instance from multiple callers at the same time is just asking for trouble.

The lock achieves the first (and simpler) of these approaches; however, another approach might be:

private static readonly ThreadLocal<Random> appRandom
     = new ThreadLocal<Random>(() => new Random());

this is then per-thread, so you don't need to synchronize.

Best Answer

Related Solutions

C# – .NET String.Format() to add commas in thousands place for a number

C# – Random number generator only generating one random number

Related Topic