Advanced C# Tips: Use Exceptions Wisely

Exceptions in C# are definitely a great facility but we need to use them wisely. We should leave the least possible probabilities of throwing an exception since exceptions come with a cost. Exceptions simply signal that something has gone wrong in your code. The purpose of an exception is to allow your program to understand and respond unexpected problems like cleaning up resources or notifying the user. However making decisions about the program’s logic is not among the primary purposes of exceptions. Even though I am talking through C#, this is true for all programming languages having exceptions. So, using exceptions for control flow is like using a sledgehammer to swat a fly. It’s not just overkill but can also introduce new problems.

The reasons why using exceptions for control flow is not advised are related to:

Performance: Exception throwing and exception catching are slow processes compared to control flow statements. If it is used in a loop or frequently called code, it causes a significant reduce in the performance.

Resource Usage: Handling exceptions requires a a certain amount of system resources. Overusing exceptions can lead to higher memory usage and slower execution times.

Readability: The code that uses exceptions for logic flow can be difficult to understand for other developers, even for yourself. Because it combines the error handling with business logic, making the code harder to follow and maintain.

Error Masking: Abuse of exceptions (I couldn’t find a better name) can make it harder to understand the difference between actual errors and flow control. This potentially masks the real issues.

Bad practice:

try
{
    var data = ReadConfig("config.txt");
}
catch (FileNotFoundException ex)
{
    var data = DefaultConfig();
}

Better approach:

if (File.Exists("config.txt"))
{
    var data = ReadConfig("config.txt");
}
else
{
    var data = DefaultConfig();
}

In the bad practice example, an exception is used to decide which configuration to load. This is inefficient and not the intended use of exceptions. A better approach can be checking for the file’s existence without resorting to exception handling as part of the logic flow. Of course, File.Exists doesn’t replace try-catch. Any step interacting with an external source must be wrapped with a try-catch blog; however, checking file existing or not in advance helps redirecting the flow to the correct pattern.

To sum up, use regular control statements (if, for, while, etc.) for flow control and use exceptions for real, genuine error conditions only. This approach keeps your code clear, efficient, and easy to maintain. Always aim for readability and performance in your error handling strategies, keeping exceptions in their rightful place as indicators of unexpected states, not as tools for regular program logic.

Suleyman Cabir Ataman, PhD

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