BigInteger.TryParse Method (String, NumberStyles, IFormatProvider, BigInteger%)

Tries to convert the string representation of a number in a specified style and culture-specific format to its BigInteger equivalent, and returns a value that indicates whether the conversion succeeded.

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

public static bool TryParse(
	string value,
	NumberStyles style,
	IFormatProvider provider,
	out BigInteger result
)

Parameters

value
Type: System.String
The string representation of a number. The string is interpreted using the style specified by style.
style
Type: System.Globalization.NumberStyles
A bitwise combination of enumeration values that indicates the style elements that can be present in value. A typical value to specify is NumberStyles.Integer.
provider
Type: System.IFormatProvider
An object that supplies culture-specific formatting information about value.
result
Type: System.Numerics.BigInteger%
When this method returns, contains the BigInteger equivalent to the number that is contained in value, or BigInteger.Zero if the conversion failed. The conversion fails if the value parameter is null or is not in a format that is compliant with style. This parameter is passed uninitialized.

Return Value

Type: System.Boolean
true if the value parameter was converted successfully; otherwise, false.

ExceptionCondition
ArgumentException

style is not a NumberStyles value.

-or-

style includes the AllowHexSpecifier or HexNumber flag along with another value.

The TryParse(String, NumberStyles, IFormatProvider, BigInteger) method is like the Parse(String, NumberStyles, IFormatProvider) method, except that it does not throw an exception if the conversion fails. This method eliminates the need to use exception handling to test for a FormatException if value is invalid and cannot be parsed successfully.

The style parameter defines the style elements (such as white space or a positive or negative sign) that are allowed in the value parameter for the parse operation to succeed. It must be a combination of bit flags from the NumberStyles enumeration. Depending on the value of style, the value parameter may include the following elements:

[ws][$][sign][digits,]digits[.fractional_digits][E[sign]exponential_digits][ws]

If the style parameter includes AllowHexSpecifier, the value parameter may include the following elements:

[ws]hexdigits[ws]

Elements in square brackets ([ and ]) are optional. The following table describes each element.

Element

Description

ws

Optional white space. White space can appear at the start of value if style includes the NumberStyles.AllowLeadingWhite flag, or at the end of value if style includes the NumberStyles.AllowTrailingWhite flag.

$

A culture-specific currency symbol. Its position in the string is defined by the CurrencyPositivePattern property of the NumberFormatInfo object returned by the GetFormat method of the provider parameter. The currency symbol can appear in value if style includes the NumberStyles.AllowCurrencySymbol flag.

sign

An optional sign. The sign can appear at the start of value if style includes the NumberStyles.AllowLeadingSign flag, and it can appear at the end of value if style includes the NumberStyles.AllowTrailingSign flag. Parentheses can be used in value to indicate a negative value if style includes the NumberStyles.AllowParentheses flag.

digits

A sequence of digits from 0 through 9.

,

A culture-specific group separator. The group separator of the culture specified by provider can appear in value if style includes the NumberStyles.AllowThousands flag.

.

A culture-specific decimal point symbol. The decimal point symbol of the culture specified by provider can appear in value if style includes the NumberStyles.AllowDecimalPoint flag.

fractional_digits

One or more occurrences of the digit 0. Fractional digits can appear in value only if style includes the NumberStyles.AllowDecimalPoint flag.

E

The "e" or "E" character, which indicates that the value is represented in exponential (scientific) notation. The value parameter can represent a number in exponential notation if style includes the NumberStyles.AllowExponent flag.

exponential_digits

A sequence of digits from 0 through 9. The value parameter can represent a number in exponential notation if style includes the NumberStyles.AllowExponent flag.

hexdigits

A sequence of hexadecimal digits from 0 through f, or 0 through F.

A string with decimal digits only (which corresponds to the NumberStyles.None flag) always parses successfully. Most of the remaining NumberStyles members control elements that may be present, but are not required to be present, in this input string. The following table indicates how individual NumberStyles members affect the elements that may be present in value.

Non-composite NumberStyles values

Elements permitted in value in addition to digits

None

Decimal digits only.

AllowDecimalPoint

The decimal point (.) and fractional_digits elements. However, fractional_digits must consist of only one or more 0 digits, or the method returns false.

AllowExponent

The "e" or "E" character, which indicates exponential notation, along with exponential_digits. If value represents a number in exponential notation, it cannot have a non-zero, fractional component.

AllowLeadingWhite

The ws element at the start of value.

AllowTrailingWhite

The ws element at the end of value.

AllowLeadingSign

The sign element before digits.

AllowTrailingSign

The sign element after digits.

AllowParentheses

The sign element in the form of parentheses enclosing the numeric value.

AllowThousands

The group separator (,) element.

AllowCurrencySymbol

The currency ($) element.

Currency

All elements. However, value cannot represent a hexadecimal number or a number in exponential notation.

Float

The ws element at the start or end of value, sign at the start of value, and the decimal point (.) symbol. The value parameter can also use exponential notation.

Number

The ws, sign, group separator (,), and decimal point (.) elements.

Any

All elements. However, value cannot represent a hexadecimal number.

Important noteImportant

If you use the TryParse method to round-trip the string representation of a BigInteger value that was output by the ToString method, you should use the BigInteger.ToString(String) method with the "R" format specifier to generate the string representation of the BigInteger value. Otherwise, the string representation of the BigInteger preserves only the 50 most significant digits of the original value, and data may be lost when you use the TryParse method to restore the BigInteger value.

If the NumberStyles.AllowHexSpecifier flag is used, value must be a hexadecimal value. The only other flags that can be present in style are NumberStyles.AllowLeadingWhite and NumberStyles.AllowTrailingWhite. (The NumberStyles enumeration has a composite style, HexNumber, that includes both white-space flags.)

NoteNote

If value is the string representation of a hexadecimal number, it cannot be preceded by any decoration (such as 0x or &h) that differentiates it as a hexadecimal number. This causes the conversion to fail.

If value is a hexadecimal string, the TryParse(String, NumberStyles, IFormatProvider, BigInteger) method interprets value as a negative number stored by using two's complement representation if its first two hexadecimal digits are greater than or equal to 0x80. In other words, the method interprets the highest-order bit of the first byte in value as the sign bit. To make sure that a hexadecimal string is correctly interpreted as a positive number, the first digit in value must have a value of zero. For example, the method interprets 0x80 as a negative value, but it interprets either 0x080 or 0x0080 as a positive value. The following example illustrates the difference between hexadecimal strings that represent negative and positive values.


using System;
using System.Globalization;
using System.Numerics;

public class Example
{
   public static void Main()
   {
      string[] hexStrings = { "80", "E293", "F9A2FF", "FFFFFFFF", 
                              "080", "0E293", "0F9A2FF", "0FFFFFFFF",  
                              "0080", "00E293", "00F9A2FF", "00FFFFFFFF" };
      BigInteger number = BigInteger.Zero;

      foreach (string hexString in hexStrings)
      {
         if (BigInteger.TryParse(hexString, NumberStyles.AllowHexSpecifier,
                                 null, out number))
            Console.WriteLine("Converted 0x{0} to {1}.", hexString, number);
         else
            Console.WriteLine("Cannot convert '{0}' to a BigInteger.", hexString);
      }
   }
}
// The example displays the following output:
//       Converted 0x80 to -128.
//       Converted 0xE293 to -7533.
//       Converted 0xF9A2FF to -417025.
//       Converted 0xFFFFFFFF to -1.
//       Converted 0x080 to 128.
//       Converted 0x0E293 to 58003.
//       Converted 0x0F9A2FF to 16360191.
//       Converted 0x0FFFFFFFF to 4294967295.
//       Converted 0x0080 to 128.
//       Converted 0x00E293 to 58003.
//       Converted 0x00F9A2FF to 16360191.
//       Converted 0x00FFFFFFFF to 4294967295.


The provider parameter is an IFormatProvider implementation. Its GetFormat method returns a NumberFormatInfo object that provides culture-specific information about the format of value. The provider parameter can be any one of the following:

If provider is null, the NumberFormatInfo object for the current culture is used.

The following example makes some calls to the TryParse(String, NumberStyles, IFormatProvider, BigInteger) method using various combinations of values for the style and provider parameters.


string numericString;
BigInteger number = BigInteger.Zero;

// Call TryParse with default values of style and provider.
numericString = "  -300   ";
if (BigInteger.TryParse(numericString, NumberStyles.Integer, 
                       null, out number))
   Console.WriteLine("'{0}' was converted to {1}.", 
                     numericString, number);                    
else
   Console.WriteLine("Conversion of '{0}' to a BigInteger failed.", 
                     numericString);

// Call TryParse with the default value of style and 
// a provider supporting the tilde as negative sign.
numericString = "  -300   ";
if (BigInteger.TryParse(numericString, NumberStyles.Integer,
                       new BigIntegerFormatProvider(), out number))
   Console.WriteLine("'{0}' was converted to {1}.",
                     numericString, number);                             
else
   Console.WriteLine("Conversion of '{0}' to a BigInteger failed.",
                     numericString);

// Call TryParse with only AllowLeadingWhite and AllowTrailingWhite.
// Method returns false because of presence of negative sign.
numericString = "  -500   ";
if (BigInteger.TryParse(numericString,
                        NumberStyles.AllowLeadingWhite | NumberStyles.AllowTrailingWhite,
                        new BigIntegerFormatProvider(), out number))
   Console.WriteLine("'{0}' was converted to {1}.",
                     numericString, number);                             
else
   Console.WriteLine("Conversion of '{0}' to a BigInteger failed.",
                     numericString);

// Call TryParse with AllowHexSpecifier and a hex value.
numericString = "F14237FFAAC086455192";
if (BigInteger.TryParse(numericString,
                        NumberStyles.AllowHexSpecifier,
                        null, out number))
   Console.WriteLine("'{0}' was converted to {1} (0x{1:x}).",
                     numericString, number);                             
else
   Console.WriteLine("Conversion of '{0}' to a BigInteger failed.",
                     numericString);

// Call TryParse with AllowHexSpecifier and a negative hex value.
// Conversion fails because of presence of negative sign.
numericString = "-3af";
if (BigInteger.TryParse(numericString, NumberStyles.AllowHexSpecifier,
                       new BigIntegerFormatProvider(), out number))
   Console.WriteLine("'{0}' was converted to {1}.",
                     numericString, number);       
else
   Console.WriteLine("Conversion of '{0}' to a BigInteger failed.",
                     numericString);

// Call TryParse with only NumberStyles.None.
// Conversion fails because of presence of white space and sign.
numericString = " -300 ";
if (BigInteger.TryParse(numericString, NumberStyles.None,
                       new BigIntegerFormatProvider(), out number))
   Console.WriteLine("'{0}' was converted to {1}.",
                     numericString, number);         
else
   Console.WriteLine("Conversion of '{0}' to a BigInteger failed.",
                     numericString);

// Call TryParse with NumberStyles.Any and a provider for the fr-FR culture.
// Conversion fails because the string is formatted for the en-US culture.
numericString = "9,031,425,666,123,546.00";
if (BigInteger.TryParse(numericString, NumberStyles.Any,
                       new CultureInfo("fr-FR"), out number))
   Console.WriteLine("'{0}' was converted to {1}.",
                     numericString, number);                     
else
   Console.WriteLine("Conversion of '{0}' to a BigInteger failed.",
                     numericString);

// Call TryParse with NumberStyles.Any and a provider for the fr-FR culture.
// Conversion succeeds because the string is properly formatted 
// For the fr-FR culture.
numericString = "9 031 425 666 123 546,00";
if (BigInteger.TryParse(numericString, NumberStyles.Any,
                       new CultureInfo("fr-FR"), out number))
   Console.WriteLine("'{0}' was converted to {1}.",
                     numericString, number);                 
else
   Console.WriteLine("Conversion of '{0}' to a BigInteger failed.",
                     numericString);
// The example displays the following output:
//    '  -300   ' was converted to -300.
//    Conversion of '  -300   ' to a BigInteger failed.
//    Conversion of '  -500   ' to a BigInteger failed.
//    'F14237FFAAC086455192' was converted to -69613977002644837412462 (0xf14237ffaac086455192).
//    Conversion of '-3af' to a BigInteger failed.
//    Conversion of ' -300 ' to a BigInteger failed.
//    Conversion of '9,031,425,666,123,546.00' to a BigInteger failed.
//    '9 031 425 666 123 546,00' was converted to 9031425666123546.      


A number of the individual calls to the TryParse(String, NumberStyles, IFormatProvider, BigInteger) method pass an instance of the following BigIntegerFormatProvider class, which defines a tilde (~) as the negative sign.


public class BigIntegerFormatProvider : IFormatProvider
{
   public object GetFormat(Type formatType) 
   {
      if (formatType == typeof(NumberFormatInfo)) 
      {
         NumberFormatInfo numberFormat = new NumberFormatInfo();
         numberFormat.NegativeSign = "~";
         return numberFormat;
      }
      else
      {
         return null;
      }      
   }
}


.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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