Bewerken

Share via


UInt32.TryParse Method

Definition

Tries to convert the string representation of a number to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

Overloads

TryParse(ReadOnlySpan<Byte>, IFormatProvider, UInt32)

Tries to parse a span of UTF-8 characters into a value.

TryParse(ReadOnlySpan<Char>, UInt32)

Tries to convert the span representation of a number to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

TryParse(String, UInt32)

Tries to convert the string representation of a number to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

TryParse(ReadOnlySpan<Char>, IFormatProvider, UInt32)

Tries to parse a span of characters into a value.

TryParse(String, IFormatProvider, UInt32)

Tries to parse a string into a value.

TryParse(ReadOnlySpan<Byte>, NumberStyles, IFormatProvider, UInt32)

Tries to parse a span of UTF-8 characters into a value.

TryParse(ReadOnlySpan<Byte>, UInt32)

Tries to convert a UTF-8 character span containing the string representation of a number to its 32-bit unsigned integer equivalent.

TryParse(ReadOnlySpan<Char>, NumberStyles, IFormatProvider, UInt32)

Tries to convert the span representation of a number in a specified style and culture-specific format to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

TryParse(String, NumberStyles, IFormatProvider, UInt32)

Tries to convert the string representation of a number in a specified style and culture-specific format to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

TryParse(ReadOnlySpan<Byte>, IFormatProvider, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs

Tries to parse a span of UTF-8 characters into a value.

public:
 static bool TryParse(ReadOnlySpan<System::Byte> utf8Text, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::UInt32 % result) = IUtf8SpanParsable<System::UInt32>::TryParse;
public static bool TryParse (ReadOnlySpan<byte> utf8Text, IFormatProvider? provider, out uint result);
static member TryParse : ReadOnlySpan<byte> * IFormatProvider * uint32 -> bool
Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), provider As IFormatProvider, ByRef result As UInteger) As Boolean

Parameters

utf8Text
ReadOnlySpan<Byte>

The span of UTF-8 characters to parse.

provider
IFormatProvider

An object that provides culture-specific formatting information about utf8Text.

result
UInt32

On return, contains the result of successfully parsing utf8Text or an undefined value on failure.

Returns

true if utf8Text was successfully parsed; otherwise, false.

Applies to

TryParse(ReadOnlySpan<Char>, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs
Source:
UInt32.cs

Important

This API is not CLS-compliant.

Tries to convert the span representation of a number to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

public:
 static bool TryParse(ReadOnlySpan<char> s, [Runtime::InteropServices::Out] System::UInt32 % result);
public static bool TryParse (ReadOnlySpan<char> s, out uint result);
[System.CLSCompliant(false)]
public static bool TryParse (ReadOnlySpan<char> s, out uint result);
static member TryParse : ReadOnlySpan<char> * uint32 -> bool
[<System.CLSCompliant(false)>]
static member TryParse : ReadOnlySpan<char> * uint32 -> bool
Public Shared Function TryParse (s As ReadOnlySpan(Of Char), ByRef result As UInteger) As Boolean

Parameters

s
ReadOnlySpan<Char>

A span containing the characters that represent the number to convert.

result
UInt32

When this method returns, contains the 32-bit unsigned integer value that is equivalent to the number contained in s, if the conversion succeeded, or zero if the conversion failed. The conversion fails if the s parameter is null or Empty, is not of the correct format, or represents a number that is less than UInt32.MinValue or greater than UInt32.MaxValue. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.

Returns

true if s was converted successfully; otherwise, false.

Attributes

Applies to

TryParse(String, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs
Source:
UInt32.cs

Important

This API is not CLS-compliant.

CLS-compliant alternative
System.Int64.TryParse(String, Int64)

Tries to convert the string representation of a number to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

public:
 static bool TryParse(System::String ^ s, [Runtime::InteropServices::Out] System::UInt32 % result);
[System.CLSCompliant(false)]
public static bool TryParse (string s, out uint result);
public static bool TryParse (string? s, out uint result);
[System.CLSCompliant(false)]
public static bool TryParse (string? s, out uint result);
[<System.CLSCompliant(false)>]
static member TryParse : string * uint32 -> bool
static member TryParse : string * uint32 -> bool
Public Shared Function TryParse (s As String, ByRef result As UInteger) As Boolean

Parameters

s
String

A string that represents the number to convert.

result
UInt32

When this method returns, contains the 32-bit unsigned integer value that is equivalent to the number contained in s, if the conversion succeeded, or zero if the conversion failed. The conversion fails if the s parameter is null or Empty, is not of the correct format, or represents a number that is less than UInt32.MinValue or greater than UInt32.MaxValue. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.

Returns

true if s was converted successfully; otherwise, false.

Attributes

Examples

The following example calls the TryParse(String, UInt32) method once for each element in a string array.

string[] numericStrings = { "1293.8", "+1671.7", "28347.",  
                            "   33113684  ", "(0)", "-0", "-1", 
                            "+1293617", "18-", "119870", "31,024", 
                            "  3127094 ", "00700000" };
uint number;
foreach (string numericString in numericStrings)
{
   if (UInt32.TryParse(numericString, out number)) 
      Console.WriteLine("Converted '{0}' to {1}.", numericString, number);
   else
      Console.WriteLine("Cannot convert '{0}' to a UInt32.", numericString);
}
// The example displays the following output:
//       Cannot convert '1293.8' to a UInt32.
//       Cannot convert '+1671.7' to a UInt32.
//       Cannot convert '28347.' to a UInt32.
//       Converted '   33113684  ' to 33113684.
//       Cannot convert '(0)' to a UInt32.
//       Converted '-0' to 0.
//       Cannot convert '-1' to a UInt32.
//       Converted '+1293617' to 1293617.
//       Cannot convert '18-' to a UInt32.
//       Converted '119870' to 119870.
//       Cannot convert '31,024' to a UInt32.
//       Converted '  3127094 ' to 3127094.
//       Converted '0070000' to 70000.
let numericStrings = 
    [| "1293.8"; "+1671.7"; "28347."
       "   33113684  "; "(0)"; "-0"; "-1" 
       "+1293617"; "18-"; "119870"; "31,024" 
       "  3127094 "; "00700000" |]

for numericString in numericStrings do
    match UInt32.TryParse numericString with
    | true, number ->
        printfn $"Converted '{numericString}' to {number}."
    | _ ->
        printfn $"Cannot convert '{numericString}' to a UInt32."
// The example displays the following output:
//       Cannot convert '1293.8' to a UInt32.
//       Cannot convert '+1671.7' to a UInt32.
//       Cannot convert '28347.' to a UInt32.
//       Converted '   33113684  ' to 33113684.
//       Cannot convert '(0)' to a UInt32.
//       Converted '-0' to 0.
//       Cannot convert '-1' to a UInt32.
//       Converted '+1293617' to 1293617.
//       Cannot convert '18-' to a UInt32.
//       Converted '119870' to 119870.
//       Cannot convert '31,024' to a UInt32.
//       Converted '  3127094 ' to 3127094.
//       Converted '0070000' to 70000.
Dim numericStrings() As String = {"1293.8", "+1671.7", "28347.", 
                                  "   33113684  ", "(0)", "-0", "-1",
                                  "+1293617", "18-", "119870", 
                                  "31,024", "  3127094 ", "0070000" }
Dim number As UInteger
For Each numericString As String In numericStrings
   If UInt32.TryParse(numericString, number) Then
      Console.WriteLine("Converted '{0}' to {1}.", numericString, number)
   Else
      Console.WriteLine("Cannot convert '{0}' to a UInt32.", numericString)
   End If      
Next
' The example displays the following output:
'       Cannot convert '1293.8' to a UInt32.
'       Cannot convert '+1671.7' to a UInt32.
'       Cannot convert '28347.' to a UInt32.
'       Converted '   33113684  ' to 33113684.
'       Cannot convert '(0)' to a UInt32.
'       Converted '-0' to 0.
'       Cannot convert '-1' to a UInt32.
'       Converted '+1293617' to 1293617.
'       Cannot convert '18-' to a UInt32.
'       Converted '119870' to 119870.
'       Cannot convert '31,024' to a UInt32.
'       Converted '  3127094 ' to 3127094.
'       Converted '0070000' to 70000.

Remarks

The TryParse method is like the Parse 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 s is invalid and cannot be successfully parsed.

The s parameter should be the string representation of a decimal number in the following form:

[ws][sign]digits[ws]

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

Element Description
ws Optional white space.
sign An optional sign. Valid sign characters are determined by the NumberFormatInfo.NegativeSign and NumberFormatInfo.PositiveSign properties of the current culture.
digits A sequence of decimal digits ranging from 0 to 9.

The s parameter is interpreted by using the NumberStyles.Integer style. In addition to the decimal digits, only leading and trailing spaces with a leading sign are allowed. To explicitly define the style elements with the culture-specific formatting information that can be present in s, call the TryParse(String, NumberStyles, IFormatProvider, UInt32) method.

Note

The string specified by the s parameter cannot contain any group separators or decimal separator, and it cannot have a fractional portion.

The s parameter is parsed by using the formatting information in a NumberFormatInfo object for the current system culture. For more information, see NumberFormatInfo.CurrentInfo.

This overload interprets all digits in the s parameter as decimal digits. To parse the string representation of a hexadecimal number, call the TryParse(String, NumberStyles, IFormatProvider, UInt32) overload instead.

See also

Applies to

TryParse(ReadOnlySpan<Char>, IFormatProvider, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs
Source:
UInt32.cs

Tries to parse a span of characters into a value.

public:
 static bool TryParse(ReadOnlySpan<char> s, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::UInt32 % result) = ISpanParsable<System::UInt32>::TryParse;
public static bool TryParse (ReadOnlySpan<char> s, IFormatProvider? provider, out uint result);
static member TryParse : ReadOnlySpan<char> * IFormatProvider * uint32 -> bool
Public Shared Function TryParse (s As ReadOnlySpan(Of Char), provider As IFormatProvider, ByRef result As UInteger) As Boolean

Parameters

s
ReadOnlySpan<Char>

The span of characters to parse.

provider
IFormatProvider

An object that provides culture-specific formatting information about s.

result
UInt32

When this method returns, contains the result of successfully parsing s, or an undefined value on failure.

Returns

true if s was successfully parsed; otherwise, false.

Applies to

TryParse(String, IFormatProvider, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs
Source:
UInt32.cs

Tries to parse a string into a value.

public:
 static bool TryParse(System::String ^ s, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::UInt32 % result) = IParsable<System::UInt32>::TryParse;
public static bool TryParse (string? s, IFormatProvider? provider, out uint result);
static member TryParse : string * IFormatProvider * uint32 -> bool
Public Shared Function TryParse (s As String, provider As IFormatProvider, ByRef result As UInteger) As Boolean

Parameters

s
String

The string to parse.

provider
IFormatProvider

An object that provides culture-specific formatting information about s.

result
UInt32

When this method returns, contains the result of successfully parsing s or an undefined value on failure.

Returns

true if s was successfully parsed; otherwise, false.

Applies to

TryParse(ReadOnlySpan<Byte>, NumberStyles, IFormatProvider, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs

Tries to parse a span of UTF-8 characters into a value.

public:
 static bool TryParse(ReadOnlySpan<System::Byte> utf8Text, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::UInt32 % result) = System::Numerics::INumberBase<System::UInt32>::TryParse;
public static bool TryParse (ReadOnlySpan<byte> utf8Text, System.Globalization.NumberStyles style, IFormatProvider? provider, out uint result);
static member TryParse : ReadOnlySpan<byte> * System.Globalization.NumberStyles * IFormatProvider * uint32 -> bool
Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), style As NumberStyles, provider As IFormatProvider, ByRef result As UInteger) As Boolean

Parameters

utf8Text
ReadOnlySpan<Byte>

The span of UTF-8 characters to parse.

style
NumberStyles

A bitwise combination of number styles that can be present in utf8Text.

provider
IFormatProvider

An object that provides culture-specific formatting information about utf8Text.

result
UInt32

On return, contains the result of successfully parsing utf8Text or an undefined value on failure.

Returns

true if utf8Text was successfully parsed; otherwise, false.

Applies to

TryParse(ReadOnlySpan<Byte>, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs

Tries to convert a UTF-8 character span containing the string representation of a number to its 32-bit unsigned integer equivalent.

public:
 static bool TryParse(ReadOnlySpan<System::Byte> utf8Text, [Runtime::InteropServices::Out] System::UInt32 % result);
public static bool TryParse (ReadOnlySpan<byte> utf8Text, out uint result);
static member TryParse : ReadOnlySpan<byte> * uint32 -> bool
Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), ByRef result As UInteger) As Boolean

Parameters

utf8Text
ReadOnlySpan<Byte>

A span containing the UTF-8 characters representing the number to convert.

result
UInt32

When this method returns, contains the 32-bit unsigned integer value equivalent to the number contained in utf8Text if the conversion succeeded, or zero if the conversion failed. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.

Returns

true if utf8Text was converted successfully; otherwise, false.

Applies to

TryParse(ReadOnlySpan<Char>, NumberStyles, IFormatProvider, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs
Source:
UInt32.cs

Important

This API is not CLS-compliant.

Tries to convert the span representation of a number in a specified style and culture-specific format to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

public:
 static bool TryParse(ReadOnlySpan<char> s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::UInt32 % result);
public:
 static bool TryParse(ReadOnlySpan<char> s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::UInt32 % result) = System::Numerics::INumberBase<System::UInt32>::TryParse;
public static bool TryParse (ReadOnlySpan<char> s, System.Globalization.NumberStyles style, IFormatProvider? provider, out uint result);
[System.CLSCompliant(false)]
public static bool TryParse (ReadOnlySpan<char> s, System.Globalization.NumberStyles style, IFormatProvider provider, out uint result);
[System.CLSCompliant(false)]
public static bool TryParse (ReadOnlySpan<char> s, System.Globalization.NumberStyles style, IFormatProvider? provider, out uint result);
static member TryParse : ReadOnlySpan<char> * System.Globalization.NumberStyles * IFormatProvider * uint32 -> bool
[<System.CLSCompliant(false)>]
static member TryParse : ReadOnlySpan<char> * System.Globalization.NumberStyles * IFormatProvider * uint32 -> bool
Public Shared Function TryParse (s As ReadOnlySpan(Of Char), style As NumberStyles, provider As IFormatProvider, ByRef result As UInteger) As Boolean

Parameters

s
ReadOnlySpan<Char>

A span containing the characters that represent the number to convert. The span is interpreted by using the style specified by the style parameter.

style
NumberStyles

A bitwise combination of enumeration values that indicates the permitted format of s. A typical value to specify is Integer.

provider
IFormatProvider

An object that supplies culture-specific formatting information about s.

result
UInt32

When this method returns, contains the 32-bit unsigned integer value equivalent to the number contained in s, if the conversion succeeded, or zero if the conversion failed. The conversion fails if the s parameter is null or Empty, is not in a format compliant with style, or represents a number that is less than UInt32.MinValue or greater than UInt32.MaxValue. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.

Returns

true if s was converted successfully; otherwise, false.

Attributes

Applies to

TryParse(String, NumberStyles, IFormatProvider, UInt32)

Source:
UInt32.cs
Source:
UInt32.cs
Source:
UInt32.cs

Important

This API is not CLS-compliant.

CLS-compliant alternative
System.Int64.TryParse(String, Int64)

Tries to convert the string representation of a number in a specified style and culture-specific format to its 32-bit unsigned integer equivalent. A return value indicates whether the conversion succeeded or failed.

public:
 static bool TryParse(System::String ^ s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::UInt32 % result);
public:
 static bool TryParse(System::String ^ s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::UInt32 % result) = System::Numerics::INumberBase<System::UInt32>::TryParse;
[System.CLSCompliant(false)]
public static bool TryParse (string s, System.Globalization.NumberStyles style, IFormatProvider provider, out uint result);
public static bool TryParse (string? s, System.Globalization.NumberStyles style, IFormatProvider? provider, out uint result);
[System.CLSCompliant(false)]
public static bool TryParse (string? s, System.Globalization.NumberStyles style, IFormatProvider? provider, out uint result);
[<System.CLSCompliant(false)>]
static member TryParse : string * System.Globalization.NumberStyles * IFormatProvider * uint32 -> bool
static member TryParse : string * System.Globalization.NumberStyles * IFormatProvider * uint32 -> bool
Public Shared Function TryParse (s As String, style As NumberStyles, provider As IFormatProvider, ByRef result As UInteger) As Boolean

Parameters

s
String

A string that represents the number to convert. The string is interpreted by using the style specified by the style parameter.

style
NumberStyles

A bitwise combination of enumeration values that indicates the permitted format of s. A typical value to specify is Integer.

provider
IFormatProvider

An object that supplies culture-specific formatting information about s.

result
UInt32

When this method returns, contains the 32-bit unsigned integer value equivalent to the number contained in s, if the conversion succeeded, or zero if the conversion failed. The conversion fails if the s parameter is null or Empty, is not in a format compliant with style, or represents a number that is less than UInt32.MinValue or greater than UInt32.MaxValue. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.

Returns

true if s was converted successfully; otherwise, false.

Attributes

Exceptions

style is not a NumberStyles value.

-or-

style is not a combination of AllowHexSpecifier and HexNumber values.

Examples

The following example calls the TryParse(String, NumberStyles, IFormatProvider, UInt32) method with a number of different strings and NumberStyles values.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      string numericString;
      NumberStyles styles;
      
      numericString = "2106034";
      styles = NumberStyles.Integer;
      CallTryParse(numericString, styles);
      
      numericString = "-10603";
      styles = NumberStyles.None;
      CallTryParse(numericString, styles);
      
      numericString = "29103674.00";
      styles = NumberStyles.Integer | NumberStyles.AllowDecimalPoint;
      CallTryParse(numericString, styles);
      
      numericString = "10345.72";
      styles = NumberStyles.Integer | NumberStyles.AllowDecimalPoint;
      CallTryParse(numericString, styles);

      numericString = "41792210E-01";
      styles = NumberStyles.Integer | NumberStyles.AllowExponent;
      CallTryParse(numericString, styles); 
      
      numericString = "9112E-01";
      CallTryParse(numericString, styles);
          
      numericString = "312E01";
      CallTryParse(numericString, styles); 
      
      numericString = "FFC86DA1";
      CallTryParse(numericString, NumberStyles.HexNumber);
      
      numericString = "0x8F8C";
      CallTryParse(numericString, NumberStyles.HexNumber);
   }
   
   private static void CallTryParse(string stringToConvert, NumberStyles styles)
   {
      uint number;
      bool result = UInt32.TryParse(stringToConvert, styles, 
                                   CultureInfo.InvariantCulture, out number);
      if (result)
         Console.WriteLine($"Converted '{stringToConvert}' to {number}.");
      else
         Console.WriteLine($"Attempted conversion of '{stringToConvert}' failed.");
   }
}
// The example displays the following output:
//       Converted '2106034' to 2106034.
//       Attempted conversion of '-10603' failed.
//       Converted '29103674.00' to 29103674.
//       Attempted conversion of '10345.72' failed.
//       Converted '41792210E-01' to 4179221.
//       Attempted conversion of '9112E-01' failed.
//       Converted '312E01' to 3120.
//       Converted 'FFC86DA1' to 4291325345.
//       Attempted conversion of '0x8F8C' failed.
open System
open System.Globalization

let callTryParse (stringToConvert: string) (styles: NumberStyles) =
    match UInt32.TryParse(stringToConvert, styles, CultureInfo.InvariantCulture) with
    | true, number ->
        printfn $"Converted '{stringToConvert}' to {number}."
        printfn $"Attempted conversion of '{stringToConvert}' failed."
    | _ -> ()

do
    let numericString = "2106034"
    let styles = NumberStyles.Integer
    callTryParse numericString styles

    let numericString = "-10603"
    let styles = NumberStyles.None
    callTryParse numericString styles

    let numericString = "29103674.00"
    let styles = NumberStyles.Integer ||| NumberStyles.AllowDecimalPoint
    callTryParse numericString styles

    let numericString = "10345.72"
    let styles = NumberStyles.Integer ||| NumberStyles.AllowDecimalPoint
    callTryParse numericString styles

    let numericString = "41792210E-01"
    let styles = NumberStyles.Integer ||| NumberStyles.AllowExponent
    callTryParse numericString styles 

    let numericString = "9112E-01"
    callTryParse numericString styles
        
    let numericString = "312E01"
    callTryParse numericString styles 

    let numericString = "FFC86DA1"
    callTryParse numericString NumberStyles.HexNumber

    let numericString = "0x8F8C"
    callTryParse numericString NumberStyles.HexNumber
   
// The example displays the following output:
//       Converted '2106034' to 2106034.
//       Attempted conversion of '-10603' failed.
//       Converted '29103674.00' to 29103674.
//       Attempted conversion of '10345.72' failed.
//       Converted '41792210E-01' to 4179221.
//       Attempted conversion of '9112E-01' failed.
//       Converted '312E01' to 3120.
//       Converted 'FFC86DA1' to 4291325345.
//       Attempted conversion of '0x8F8C' failed.
Imports System.Globalization

Module Example
   Public Sub Main()
      Dim numericString As String
      Dim styles As NumberStyles
      
      numericString = "2106034"
      styles = NumberStyles.Integer
      CallTryParse(numericString, styles)
      
      numericString = "-10603"
      styles = NumberStyles.None
      CallTryParse(numericString, styles)
      
      numericString = "29103674.00"
      styles = NumberStyles.Integer Or NumberStyles.AllowDecimalPoint
      CallTryParse(numericString, styles)
      
      numericString = "10345.72"
      styles = NumberStyles.Integer Or NumberStyles.AllowDecimalPoint
      CallTryParse(numericString, styles)

      numericString = "41792210E-01"
      styles = NumberStyles.Integer Or NumberStyles.AllowExponent
      CallTryParse(numericString, styles) 
      
      numericString = "9112E-01"
      CallTryParse(numericString, styles)
          
      numericString = "312E01"
      CallTryParse(numericString, styles) 
      
      numericString = "FFC86DA1"
      CallTryParse(numericString, NumberStyles.HexNumber)
      
      numericString = "0x8F8C"
      CallTryParse(numericString, NumberStyles.HexNumber)
   End Sub
   
   Private Sub CallTryParse(stringToConvert As String, styles AS NumberStyles)
      Dim number As UInteger
      Dim result As Boolean = UInt32.TryParse(stringToConvert, styles, _
                                              CultureInfo.InvariantCulture, number)
      If result Then
         Console.WriteLine("Converted '{0}' to {1}.", stringToConvert, number)
      Else
         Console.WriteLine("Attempted conversion of '{0}' failed.", _
                           Convert.ToString(stringToConvert))
      End If                                                                           
   End Sub
End Module
' The example displays the following output to the console:
'       Converted '2106034' to 2106034.
'       Attempted conversion of '-10603' failed.
'       Converted '29103674.00' to 29103674.
'       Attempted conversion of '10345.72' failed.
'       Converted '41792210E-01' to 4179221.
'       Attempted conversion of '9112E-01' failed.
'       Converted '312E01' to 3120.
'       Converted 'FFC86DA1' to 4291325345.
'       Attempted conversion of '0x8F8C' failed.

Remarks

The TryParse(String, NumberStyles, IFormatProvider, UInt32) 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 s 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 s 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 s parameter may include the following elements:

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

Items in square brackets ([ and ]) are optional. Or, if the style parameter includes NumberStyles.AllowHexSpecifier, the s parameter may include the following elements:

[ws]hexdigits[ws]

The following table describes each element.

Element Description
ws Optional white space. White space can appear at the start of s if style includes the NumberStyles.AllowLeadingWhite flag, or at the end of s 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 s if style includes the NumberStyles.AllowCurrencySymbol flag.
sign An optional sign. The sign can appear at the start of s if style includes the NumberStyles.AllowLeadingSign flag, and it can appear at the end of s if style includes the NumberStyles.AllowTrailingSign flag. Parentheses can be used in s to indicate a negative value if style includes the NumberStyles.AllowParentheses flag. However, if the negative sign is present, s can only represent the value zero for the parse operation to succeed.
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 s 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 s if style includes the NumberStyles.AllowDecimalPoint flag.
fractional_digits One or more occurrences of the digit 0. Fractional digits can appear in s 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 s 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 s 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.

Note

Any terminating NUL (U+0000) characters in s are ignored by the parsing operation, regardless of the value of the style argument.

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 s.

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 s represents a number in exponential notation, it cannot have a non-zero, fractional component.
AllowLeadingWhite The ws element at the start of s.
AllowTrailingWhite The ws element at the end of s.
AllowLeadingSign The sign element before digits.
AllowTrailingSign The sign element after digits.
AllowParentheses The sign element in the form of parentheses enclosing a zero numeric value.
AllowThousands The group separator (,) element.
AllowCurrencySymbol The currency ($) element.
Currency All elements. However, s cannot represent a hexadecimal number or a number in exponential notation.
Float The ws element at the start or end of s, sign at the start of s, and the decimal point (.) symbol. The s parameter can also use exponential notation.
Number The ws, sign, group separator (,), and decimal point (.) elements.
Any All elements. However, s cannot represent a hexadecimal number.

If the NumberStyles.AllowHexSpecifier flag is used, s 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.)

Note

If s 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.

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

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

See also

Applies to