Question

I have a large project in C# (.NET 2.0) which contains very large chunks of code generated by SubSonic. Is a try-catch like this causing a horrible performance hit?

    for (int x = 0; x < identifiers.Count; x++)
            {decimal target = 0;
                try
                {
                    target = Convert.ToDecimal(assets[x + identifiers.Count * 2]); // target %
                }
                catch { targetEmpty = true;  }}

What is happening is if the given field that is being passed in is not something that can be converted to a decimal it sets a flag which is then used further along in the record to determine something else.

The problem is that the application is literally throwing 10s of thousands of exceptions as I am parsing through 30k records. The process as a whole takes almost 10 minutes for everything and my overall task is to improve that time some and this seemed like easy hanging fruit if its a bad design idea.

Any thoughts would be helpful (be kind, its been a miserable day)

thanks,
Chris

Answer 1

Using exceptions for control flow is generally a bad practice (exactly because of the poor efficiency that you’re observing). What type of data do you need to convert to decimal? Could you use TryParse method or some other method that doesn’t throw exception if the input is not in the expected format?

Decimal.TryParse method should do the trick if you’re parsing strings as it reports failure by returnning false:

decimal d;
if (Decimal.TryParse(str, out d)) 
  // Ok, use decimal 'd'
else 
  // Failed - do something else