Throw and rethrow patterns in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to rethrow the caught exception preserving the original stack trace.

C Sharp (C#)

try {
    // Some code
} catch (Exception ex) {
    [1];
}

Drag options to blanks, or click blank then click option'

Athrow ex

Bthrow new Exception()

Cthrow

Dthrow ex.InnerException

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'throw ex' which resets the stack trace.

Throwing a new exception loses original exception details.

Using throw alone rethrows the current exception preserving the original stack trace.

2fill in blank

medium

Complete the code to throw a new exception with a custom message inside the catch block.

C Sharp (C#)

try {
    // Some code
} catch (Exception ex) {
    throw new Exception([1], ex);
}

Drag options to blanks, or click blank then click option'

Aex.Message

Bnull

Cex

D"Error occurred"

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the exception object instead of a message string.

Using null instead of a descriptive message.

The first argument is the custom message string for the new exception.

3fill in blank

hard

Fix the error in the catch block to correctly rethrow the exception preserving the stack trace.

C Sharp (C#)

try {
    // Some code
} catch (Exception ex) {
    [1];
}

Drag options to blanks, or click blank then click option'

Athrow

Bthrow new Exception(ex.Message)

Cthrow ex

Dthrow ex.InnerException

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'throw ex' which resets the stack trace.

Throwing a new exception loses original stack trace.

Using throw alone rethrows the original exception with its stack trace intact.

4fill in blank

hard

Fill both blanks to create a try-catch that logs the exception message and then rethrows it preserving the stack trace.

C Sharp (C#)

try {
    // Some code
} catch (Exception ex) {
    Console.[1](ex.Message);
    [2];
}

Drag options to blanks, or click blank then click option'

AWriteLine

BWrite

Cthrow

Dthrow ex

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'throw ex' which resets the stack trace.

Using Console.Write instead of WriteLine for logging.

Use Console.WriteLine to print the message and throw to rethrow preserving the stack trace.

5fill in blank

hard

Fill all three blanks to catch an exception, wrap it in a new exception with a custom message, and throw it.

C Sharp (C#)

try {
    // Some code
} catch (Exception [1]) {
    throw new Exception([2], [3]);
}

Drag options to blanks, or click blank then click option'

Aex

B"Custom error occurred"

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different variable name than declared in catch.

Passing the wrong type as the message argument.

Not passing the original exception as inner exception.

The catch variable is named ex. The new exception message is a string, and the original exception ex is passed as inner exception.