Learn to enhance your C# code’s readability by avoiding multiple catch blocks. Discover a better approach using Exception Filters on Day 25 of our 30-Day .NET Challenge.
Introduction
The article demonstrates the use of exception filters to improve the readability, maintainability and performance of the application.
Learning Objectives
The problem with traditional exception handling
Efficient exception handling using filters.
Prerequisites for Developers
- Basic understanding of C# programming language.
Getting Started
The problem with traditional exception handling
Traditionally, developers often use simple catch blocks to handle exceptions and use conditional logic to handle specific exception types. Please find below the code snippet demonstrating the traditional approach
try
{
// Perform an operation
}
catch (Exception ex)
{
if (ex is InvalidOperationException || ex is ArgumentNullException)
{
// Handle the specific exceptions
}
else
{
throw; // Rethrow the exception if it's not one we're specifically handling
}
}
Using conditional statements with an if block creates a code which is hard to maintain and doesn’t look very readable.
Efficient exception handling using filters
Please find below the refactored version of the previous code snippet
try
{
// Perform an operation
}
catch (Exception ex) when (ex is InvalidOperationException || ex is ArgumentNullException)
{
// Handle only InvalidOperationException or ArgumentNullException
}
The approach above improves the readability and maintainability of the code. In addition to that, it enhances the performance as the catch block is executed only when the filter evaluates to be true as catching an exception is an expensive operation. Only when the filter returns a true, the stack trace will be captured,
Complete Code
Create another class named ExceptionFilters and add the following code snippet
public static class ExceptionFilters
{
public static void MultipleCatch(string input)
{
try
{
ProcessInput(input);
}
catch (Exception ex)
{
if (ex is InvalidOperationException || ex is ArgumentNullException)
{
Console.WriteLine($"Conventional Handling: Caught {ex.GetType().Name}");
}
else
{
throw;
}
}
}
public static void GoodWay(string input)
{
// Using exception filters
try
{
ProcessInput(input);
}
catch (Exception ex) when (ex is InvalidOperationException || ex is ArgumentNullException)
{
Console.WriteLine($"Exception Filters Handling: Caught {ex.GetType().Name}");
}
}
public static void ProcessInput(string input)
{
if (input == null)
throw new ArgumentNullException(nameof(input), "Input cannot be null.");
else if (input == "invalid")
throw new InvalidOperationException("Invalid input provided.");
Console.WriteLine($"Processing {input}");
}
}
Execute from the main method as follows
#region Day 25: Use Exception Filters
static string ExecuteDay25()
{
// Using conventional exception handling
// This will cause ArgumentNullException
ExceptionFilters.MultipleCatch(null);
// Reset input for valid processing
ExceptionFilters.GoodWay("Valid input");
// This input will cause InvalidOperationException
ExceptionFilters.GoodWay("invalid");
return "Executed Day 25 successfully..!!";
}
#endregion
Console Output
Conventional Handling: Caught ArgumentNullException
Processing Valid input
Exception Filters Handling: Caught InvalidOperationException
Complete Code on GitHub
GitHub — ssukhpinder/30DayChallenge.Net
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