C# | Convert.ToUInt64(String, IFormatProvider) Method

Last Updated : 11 Jul, 2025

This method is used to converts the specified string representation of a number to an equivalent 64-bit unsigned integer, using the specified culture-specific formatting information. 

Syntax:

public static ulong ToUInt64 (string value, IFormatProvider provider);

Parameters:

  • value: It is a string that contains the number to convert.
  • provider: It is an object that supplies culture-specific formatting information.

Return Value: This method returns a 64-bit unsigned integer that is equivalent to the number in value, or 0 (zero) if value is null. 

Exceptions:

  • FormatException: If the value does not consist of an optional sign followed by a sequence of digits (0 through 9).
  • OverflowException: If the value represents a number that is less than MinValue or greater than MaxValue.

Below programs illustrate the use of Convert.ToUInt64(String, IFormatProvider) Method: 

Example 1: 

csharp 
// C# program to demonstrate the
// Convert.ToUInt64() Method
using System;
using System.Globalization;

class GFG {

// Main Method
public static void Main()
{
    try {

        // creating object of CultureInfo
        CultureInfo cultures = new CultureInfo("en-US");

        // declaring and initializing String array
        string[] values = {"123456789012",
                           "+123456789012", 
                   "18446744073709551615"};

        // calling get() Method
        Console.WriteLine("Converted ulong value"
              + " from a specified string ");

        for (int j = 0; j < values.Length; j++)
        {
            get(values[j], cultures);
        }
    }

    catch (FormatException e) 
    {
        Console.WriteLine("\n");
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }

    catch (OverflowException e)
    {
        Console.WriteLine("\n");
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }
}

// Defining get() method
public static void get(string s,
          CultureInfo cultures)
{

    // converting string to specified ulong
    ulong val = Convert.ToUInt64(s, cultures);

    // display the converted ulong value
    Console.Write(" {0}, ", val);
}
}
Output:
Converted ulong value from a specified string 
 123456789012,  123456789012,  18446744073709551615,

Example 2: For FormatException 

csharp 
// C# program to demonstrate the
// Convert.ToUInt64() Method
using System;
using System.Globalization;

class GFG {

// Main Method
public static void Main()
{

    try {

        // creating object of CultureInfo
        CultureInfo cultures = new CultureInfo("en-US");

    // declaring and initializing String array
        string[] values = {"123456789012",
                           "+123456789012", 
                   "18446744073709551615"};


        // calling get() Method
        Console.WriteLine("Converted ulong value"
                    + " of specified strings: ");

        for (int j = 0; j < values.Length; j++)
        {
            get(values[j], cultures);
        }

        Console.WriteLine("\n");
        string s = "123 456, 789";

        Console.WriteLine("format of s is invalid ");

        // converting string to specified ulong
        long val = Convert.ToUInt64(s, cultures);

        // display the converted ulong value
        Console.Write(" {0}, ", val);
    }

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

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

// Defining get() method
public static void get(string s,
           CultureInfo cultures)
{

    // converting string to
    // specified ulong value
    ulong val = Convert.ToUInt64(s, 
                         cultures);

    // display the converted
    // ulong value
    Console.Write(" {0}, ", val);
}
}
Output:
Converted ulong value of specified strings: 
 123456789012,  123456789012,  18446744073709551615, 

format of s is invalid 
Exception Thrown: System.FormatException

Example 3: For OverflowException 

csharp 
// C# program to demonstrate the
// Convert.ToUInt64() Method
using System;
using System.Globalization;

class GFG {

// Main Method
public static void Main()
{

    try {

        // creating object of CultureInfo
        CultureInfo cultures = new CultureInfo("en-US");

        // declaring and initializing String array
        string[] values = {"123456789012",
                          "+123456789012", 
                  "18446744073709551615"};


        // calling get() Method
        Console.WriteLine("Converted ulong value "
                  + "of specified strings: ");

        for (int j = 0; j < values.Length; j++)
        {
            get(values[j], cultures);
        }

        Console.WriteLine("\n");
        string s = "-7922816251426433759354395033500000";

        Console.WriteLine("s is less than the MinValue");

        // converting string to specified ulong
        ulong val = Convert.ToUInt64(s, cultures);

        // display the converted ulong value
        Console.Write(" {0}, ", val);
    }

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

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

// Defining get() method
public static void get(string s,
           CultureInfo cultures)
{

    // converting string to
    // specified ulong value
    ulong val = Convert.ToUInt64(s, cultures);

    // display the converted ulong value
    Console.Write(" {0}, ", val);
}
}
Output:
Converted ulong value of specified strings: 
 123456789012,  123456789012,  18446744073709551615, 

s is less than the MinValue
Exception Thrown: System.OverflowException

Reference:

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Article Tags:
C#
CSharp-method
CSharp Convert Class

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