Bits of .NET

🛡️ Exception Handling = Robust Code

Apps crash without error handling. Try-catch handles errors gracefully. Robust, reliable apps.

📝 Try-Catch Basics

try
{
    // Code that might throw
    int result = int.Parse(input);
    Console.WriteLine($"Result: {result}");
}
catch (FormatException ex)
{
    Console.WriteLine($"Invalid format: {ex.Message}");
}
catch (OverflowException ex)
{
    Console.WriteLine($"Number too large: {ex.Message}");
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
    throw;
}
finally
{
    Console.WriteLine("Operation completed");
}

// Using with IDisposable
using (var connection = new SqlConnection(connectionString))
{
    // Auto-disposed
}

🎯 Advanced Patterns

// Custom exception
public class ValidationException : Exception
{
    public ValidationException(string message) : base(message) { }
    public ValidationException(string message, Exception inner) : base(message, inner) { }
}

// Try pattern
public bool TryParseInt(string input, out int result)
{
    try
    {
        result = int.Parse(input);
        return true;
    }
    catch
    {
        result = 0;
        return false;
    }
}

// Exception filters
try
{
    // Some code
}
catch (Exception ex) when (ex is TimeoutException || ex is SqlException)
{
    // Handle specific errors only
}

// Throw with inner exception
try
{
    // Some code
}
catch (Exception ex)
{
    throw new ApplicationException("Failed to process", ex);
}

// Global exception handling
public class GlobalExceptionHandler
{
    public static async Task HandleException(Exception ex, ILogger logger)
    {
        logger.LogError(ex, "Unhandled exception");
        throw ex;
    }
}

✅ Exception Tips

• Don’t catch exceptions you can’t handle
• Use specific exception types
• Log all exceptions with context
• Use finally for cleanup
• Use using for IDisposable resources