try catch finally

Context: The try-catch-finally block is the fundamental mechanism for handling exceptions in C#. Code that may throw an exception is placed in the try block. If an exception occurs, control transfers to the appropriate catch block. The finally block executes regardless of whether an exception was thrown, and is typically used for cleanup (closing files, releasing resources). The finally block is optional but recommended for deterministic cleanup.

Usage Example

using System;
using System.IO;

class Program
{
    static void Main()
    {
        StreamReader reader = null;
        try
        {
            reader = new StreamReader("nonexistent.txt");
            string content = reader.ReadToEnd();
            Console.WriteLine(content);
        }
        catch (FileNotFoundException ex)
        {
            Console.WriteLine($"File not found: {ex.Message}");
        }
        finally
        {
            reader?.Dispose();
            Console.WriteLine("Cleanup completed.");
        }
    }
}

Output console

dotnet run
File not found: Could not find file 'nonexistent.txt'.
Cleanup completed.

Important notes

The finally block always runs, even if no exception occurs or if a return is inside try.
You can have try-finally without catch.
Never throw exceptions from finally blocks (they can hide original exceptions).

Real-world usage example

Database connection handling – Using try-catch-finally to ensure SqlConnection is closed even if a query fails.
See .NET docs on try-catch-finally.

try catch finally

Usage Example

Output console

Important notes

Real-world usage example

Related sections