ISBNValidator Class

The ISBNValidator class provides methods to validate ISBNs (International Standard Book Numbers), including checking if they are valid, formatted, and follow the ISBN-10 or ISBN-13 standard.

Methods

IsValidISBN

public static bool IsValidISBN(string isbn)

The IsValidISBN method validates whether the given ISBN is valid and follows the specified ISBN version (ISBN-10 or ISBN-13).

Parameters

• isbn (string): The ISBN to validate.

Returns

• true if the ISBN is valid and follows the specified version (ISBN-10 or ISBN-13).
• false if the ISBN is not valid or does not follow the specified version.

Remarks

• The ISBN must not be null, empty, or contain only whitespace characters.
• The method removes any spaces or dashes from the ISBN before validation.
• The ISBN must be correctly formatted according to the specified version (ISBN-10 or ISBN-13).
• For ISBN-10, the ISBN must consist of 10 digits (either numeric or with the last character being 'X' for the check digit).
• For ISBN-13, the ISBN must consist of 13 digits (numeric only) and follow the EAN-13 format.

IsValidISBN10

public static bool IsValidISBN10(string isbn)

The IsValidISBN10 method checks if a given string is a valid ISBN-10 number.

Parameters

• isbn (string): The string to check.

Returns

• true if the string is a valid ISBN-10 number.
• false otherwise.

Remarks

• The method removes any spaces or dashes from the input string before validation.
• The ISBN must not be null, empty, or contain only whitespace characters.
• The ISBN must consist of 10 digits (either numeric or with the last character being 'X' for the check digit).
• The method performs the ISBN-10 validation using the modulus 11 algorithm:

1. Multiply each of the first nine digits of the ISBN by a weight, starting from 10 and decreasing by 1 for each digit.
2. Sum the results of the multiplication.
3. If the last character of the ISBN is 'X', add 10 to the sum; otherwise, add the value of the last digit.
4. The ISBN is valid if the sum is divisible by 11 (i.e., (sum % 11) == 0).

IsValidISBN13

public static bool IsValidISBN13(string isbn)

The IsValidISBN13 method checks if a given string is a valid ISBN-13 number.

Parameters

• isbn (string): The string to check.

Returns

• true if the string is a valid ISBN-13 number.
• false otherwise.

Remarks

• The method removes any spaces or dashes from the input string before validation.
• The ISBN must not be null, empty, or contain only whitespace characters.
• The ISBN must consist of 13 digits (numeric only) and follow the EAN-13 format.
• The method performs the ISBN-13 validation using the EAN-13 check digit calculation:

1. Multiply each of the first 12 digits of the ISBN by a weight, alternating between 1 and 3 for each digit.
2. Sum the results of the multiplication.
3. Calculate the check digit as follows: checksum = 10 - (sum % 10), or 0 if (sum % 10) == 0.
4. The ISBN is valid if the last digit of the ISBN matches the calculated check digit.

Example

using XValid;

string isbn10 = "0-306-40615-2"; // Example ISBN-10
string isbn13 = "978-3-16-148410-0"; // Example ISBN-13

bool isValidISBN10 = ISBNValidator.IsValidISBN(isbn10);
bool isValidISBN13 = ISBNValidator.IsValidISBN(isbn13);

if (isValidISBN10)
{
    Console.WriteLine("Valid ISBN-10!");
}
else
{
    Console.WriteLine("Invalid ISBN-10!");
}

if (isValidISBN13)
{
    Console.WriteLine("Valid ISBN-13!");
}
else
{
    Console.WriteLine("Invalid ISBN-13!");
}

That's it! You can use the ISBNValidator class in your C# code to validate ISBNs and ensure they are correctly formatted according to the ISBN-10 or ISBN-13 standard. If you have any questions or need more information, feel free to explore other sections of the API reference or check out the Get Started page for an overview of XValid.