"throw "and "throw new" Exception()

In C#, the throw statement is used to explicitly throw an exception, while throw new is used to throw a new instance of an exception. Let's investigate into the details of each approach, along with examples:

throw

The throw statement allows you to raise an exception explicitly without creating a new instance of an exception. It is typically used when you want to rethrow an exception that was caught earlier, propagate an existing exception up the call stack, or throw a predefined exception.

Rethrowing an Exception
try { // Some code that can potentially throw an exception } catch (Exception ex) { // Perform some handling or logging // Rethrow the exception throw; }

In the above example, the throw; statement is used inside a catch block to rethrow the caught exception. This allows the exception to be propagated up the call stack for further handling or logging.

throw new Exception()

The throw new syntax is used to create a new instance of an exception and throw it. This approach is commonly used when you want to throw a specific exception type with custom information, such as an error message or additional data.

Throwing a Custom Exception
if (someCondition) { // Throw a custom exception throw new InvalidOperationException("Invalid operation!"); }

In the above example, the throw new syntax is used to create and throw a new instance of the InvalidOperationException class. It allows you to provide a custom error message that describes the reason for the exception.

Throwing a System Exception
if (someCondition) { // Throw a system exception throw new ArgumentException("Invalid argument!"); }

In this example, the throw new syntax is used to throw a new instance of the ArgumentException class, which is a built-in exception type in .NET.

Conclusion

The throw statement is used to propagate an existing exception or rethrow a caught exception, while throw new is used to create and throw a new instance of an exception. The throw statement is useful when you want to pass an exception up the call stack, while throw new allows you to create and throw a specific exception type with custom information. Both approaches are important for exception handling and error propagation in C#.