Convert.ToUInt64 Method (String, IFormatProvider)

Converts the specified String representation of a number to an equivalent 64-bit unsigned integer using the specified culture-specific formatting information.

This API is not CLS-compliant. 

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public static ulong ToUInt64(
	string value,
	IFormatProvider provider


Type: System.String
A String containing a number to convert.
Type: System.IFormatProvider
An IFormatProvider interface implementation that supplies culture-specific formatting information.

Return Value

Type: System.UInt64
A 64-bit unsigned integer equivalent to the value of value.
Zero if value is null.


value does not consist of an optional sign followed by a sequence of digits (zero through nine).


value represents a number less than MinValue or greater than MaxValue.

The return value is the result of invoking UInt64.Parse on value.

provider is an IFormatProvider instance that obtains a NumberFormatInfo object. The NumberFormatInfo object provides culture-specific information about the format of value. If provider is null, the NumberFormatInfo for the current culture is used.

If you prefer not to handle an exception if the conversion fails, you can call the UInt64.TryParse method instead. It returns a Boolean value that indicates whether the conversion succeeded or failed.

The following code example converts String representations of 64-bit unsigned integers with the ToUInt64 method, using an IFormatProvider object.

// Example of the Convert.ToUInt64( string ) and 
// Convert.ToUInt64( string, IFormatProvider ) methods.
using System;
using System.Globalization;

class Example
   static string format = "{0,-24}{1,-22}{2}";

   // Get the exception type name; remove the namespace prefix.
   static string GetExceptionType(Exception ex)
      string exceptionType = ex.GetType().ToString();
      return exceptionType.Substring(
          exceptionType.LastIndexOf('.') + 1);

   static void ConvertToUInt64(System.Windows.Controls.TextBlock outputBlock, string numericStr,
       IFormatProvider provider)
      object defaultValue;
      object providerValue;

      // Convert numericStr to UInt64 without a format provider.
         defaultValue = Convert.ToUInt64(numericStr);
      catch (Exception ex)
         defaultValue = GetExceptionType(ex);

      // Convert numericStr to UInt64 with a format provider.
         providerValue = Convert.ToUInt64(numericStr, provider);
      catch (Exception ex)
         providerValue = GetExceptionType(ex);

      outputBlock.Text += String.Format(format, numericStr,
          defaultValue, providerValue) + "\n";

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
      // Create a NumberFormatInfo object and set several of its
      // properties that apply to numbers.
      NumberFormatInfo provider = new NumberFormatInfo();

      // These properties affect the conversion.
      provider.NegativeSign = "neg ";
      provider.PositiveSign = "pos ";

      // These properties do not affect the conversion.
      // The input string cannot have decimal and group separators.
      provider.NumberDecimalSeparator = ".";
      provider.NumberGroupSeparator = ",";
      provider.NumberGroupSizes = new int[] { 3 };

      outputBlock.Text += String.Format("This example of\n" +
          "  Convert.ToUInt64( string ) and \n" +
          "  Convert.ToUInt64( string, IFormatProvider ) " +
          "\ngenerates the following output. It converts " +
          "several strings to \nulong values, using " +
          "default formatting or a NumberFormatInfo object.\n") + "\n";
      outputBlock.Text += String.Format(format, "String to convert",
          "Default/exception", "Provider/exception") + "\n";
      outputBlock.Text += String.Format(format, "-----------------",
          "-----------------", "------------------") + "\n";

      // Convert strings, with and without an IFormatProvider.
      ConvertToUInt64(outputBlock, "123456789012", provider);
      ConvertToUInt64(outputBlock, "+123456789012", provider);
      ConvertToUInt64(outputBlock, "pos 123456789012", provider);
      ConvertToUInt64(outputBlock, "123456789012.", provider);
      ConvertToUInt64(outputBlock, "123,456,789,012", provider);
      ConvertToUInt64(outputBlock, "18446744073709551615", provider);
      ConvertToUInt64(outputBlock, "18446744073709551616", provider);
      ConvertToUInt64(outputBlock, "-1", provider);

This example of
  Convert.ToUInt64( string ) and
  Convert.ToUInt64( string, IFormatProvider )
generates the following output. It converts several strings to
ulong values, using default formatting or a NumberFormatInfo object.

String to convert       Default/exception     Provider/exception
-----------------       -----------------     ------------------
123456789012            123456789012          123456789012
+123456789012           123456789012          FormatException
pos 123456789012        FormatException       123456789012
123456789012.           FormatException       FormatException
123,456,789,012         FormatException       FormatException
18446744073709551615    18446744073709551615  18446744073709551615
18446744073709551616    OverflowException     OverflowException
-1                      OverflowException     FormatException


Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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