Int64.Parse(String) Method in C# with Examples

Int64.Parse(String) Method is used to convert the string representation of a number to its 64-bit signed integer equivalent.

Syntax:

public static long Parse (string str);

Here, str is a string containing a number to convert. The format of str will be [optional white space][optional sign]digits[optional white space].

Return Value: It is a 64-bit signed integer equivalent to the number contained in str.

Exceptions:

• ArgumentNullException: If str is null.
• FormatException: If str is not in the correct format.
• OverflowException: If str represents a number less than MinValue or greater than MaxValue.

Below programs illustrate the use of above-discussed method:

Example 1:

// C# program to demonstrate
// Int64.Parse(String) Method
using System;

class GFG {

    // Main Method
    public static void Main()
    {

        // passing different values
        // to the method to check
        checkParse("9223372036854775807");
        checkParse("29,22337,20368547");
        checkParse("-922337203685477");
        checkParse(" 9223372075807");
    }

    // Defining checkParse method
    public static void checkParse(string input)
    {

        try {

            // declaring Int64 variable
            long val;

            // getting parsed value
            val = Int64.Parse(input);
            Console.WriteLine("'{0}' parsed as {1}", input, val);
        }

        catch (FormatException)
        {
            Console.WriteLine("Can't Parsed '{0}'", input);
        }
    }
}

Output:

'9223372036854775807' parsed as 9223372036854775807
Can't Parsed '29,22337,20368547'
'-922337203685477' parsed as -922337203685477
' 9223372075807' parsed as 9223372075807

Example 2: For ArgumentNullException

// C# program to demonstrate
// Int64.Parse(String) Method
// for ArgumentNullException
using System;

class GFG {

    // Main Method
    public static void Main()
    {

        try {

            // passing null value as a input
            checkParse(null);
        }

        catch (ArgumentNullException e) {

            Console.Write("Exception Thrown: ");
            Console.Write("{0}", e.GetType(), e.Message);
        }

        catch (FormatException e) {

            Console.Write("Exception Thrown: ");
            Console.Write("{0}", e.GetType(), e.Message);
        }
    }

    // Defining checkparse method
    public static void checkParse(string input)
    {

        // declaring Int64 variable
        long val;

        // getting parsed value
        val = Int64.Parse(input);
        Console.WriteLine("'{0}' parsed as {1}", input, val);
    }
}

Output:

Exception Thrown: System.ArgumentNullException

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.int64.parse?view=netframework-4.7.2#System_Int64_Parse_System_String_