Why to use "finally" block in C#?

The usage of a finally block provides a mechanism to perform resource cleanup for any allocated resources within a try block, regardless of whether an exception is thrown or the code executes successfully. Its purpose is to ensure the proper release of valuable resources, such as limited quantity database connections, regardless of the outcome of the code execution. The execution of the finally block is specifically intended for the purpose of releasing these resources, thereby promoting efficient resource management and preventing resource leaks.

Example
var connection = new SqlConnection(); connection.Open() try { // execute a command } catch { // handle an exception } finally { // do any required cleanup // if the code executes with or without an exception, we have to close connection here connection.Close(); }

The code contained within a finally block in C# will be executed regardless of whether an exception occurs or not. The primary purpose of the finally block is to handle necessary cleanup operations or dispose of resources. However, it is worth noting that when it comes to resource disposal, using blocks are often considered a better approach.

Throwing exceptions

It is important to be aware that a finally block should not throw exceptions unless explicitly intended by the system design. Throwing exceptions within a finally block is generally considered bad practice. The finally block is primarily meant for ensuring cleanup operations and should not introduce additional exceptions that can complicate the exception handling flow.

In C#, the using statement provides a convenient and recommended way to handle the disposal of IDisposable objects. The using statement automatically takes care of calling the Dispose() method on the object, guaranteeing proper resource cleanup even if exceptions occur within the block.

Conclusion

The finally block in C# ensures that the code inside it will execute irrespective of whether an exception is thrown or not. It is commonly used for cleanup purposes, although using blocks are typically preferred for resource disposal. It is essential to exercise caution and avoid throwing exceptions within a finally block, and instead utilize the using statement for convenient and safe resource management.