Int32.TryParse Method
Definition
Important
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Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the operation succeeded.
Overloads
TryParse(String, IFormatProvider, Int32) |
Tries to parse a string into a value. |
TryParse(ReadOnlySpan<Char>, Int32) |
Converts the span representation of a number in a culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded. |
TryParse(String, Int32) |
Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded. |
TryParse(ReadOnlySpan<Byte>, IFormatProvider, Int32) |
Tries to parse a span of UTF-8 characters into a value. |
TryParse(ReadOnlySpan<Char>, IFormatProvider, Int32) |
Tries to parse a span of characters into a value. |
TryParse(ReadOnlySpan<Byte>, NumberStyles, IFormatProvider, Int32) |
Tries to parse a span of UTF-8 characters into a value. |
TryParse(ReadOnlySpan<Byte>, Int32) |
Tries to convert a UTF-8 character span containing the string representation of a number to its 32-bit signed integer equivalent. |
TryParse(ReadOnlySpan<Char>, NumberStyles, IFormatProvider, Int32) |
Converts the span representation of a number in a specified style and culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded. |
TryParse(String, NumberStyles, IFormatProvider, Int32) |
Converts the string representation of a number in a specified style and culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded. |
TryParse(String, IFormatProvider, Int32)
- Source:
- Int32.cs
- Source:
- Int32.cs
- Source:
- Int32.cs
Tries to parse a string into a value.
public:
static bool TryParse(System::String ^ s, IFormatProvider ^ provider, [Runtime::InteropServices::Out] int % result) = IParsable<int>::TryParse;
public static bool TryParse (string? s, IFormatProvider? provider, out int result);
static member TryParse : string * IFormatProvider * int -> bool
Public Shared Function TryParse (s As String, provider As IFormatProvider, ByRef result As Integer) As Boolean
Parameters
- s
- String
The string to parse.
- provider
- IFormatProvider
An object that provides culture-specific formatting information about s
.
- result
- Int32
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<Char>, Int32)
- Source:
- Int32.cs
- Source:
- Int32.cs
- Source:
- Int32.cs
Converts the span representation of a number in a culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.
public:
static bool TryParse(ReadOnlySpan<char> s, [Runtime::InteropServices::Out] int % result);
public static bool TryParse (ReadOnlySpan<char> s, out int result);
static member TryParse : ReadOnlySpan<char> * int -> bool
Public Shared Function TryParse (s As ReadOnlySpan(Of Char), ByRef result As Integer) As Boolean
Parameters
- s
- ReadOnlySpan<Char>
A span containing the characters that represent the number to convert.
- result
- Int32
When this method returns, contains the 32-bit signed integer value equivalent of 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 or represents a number less than Int32.MinValue or greater than Int32.MaxValue. This parameter is passed uninitialized; any value originally supplied in result
will be overwritten.
Returns
true
if s
was converted successfully; otherwise, false
.
Applies to
TryParse(String, Int32)
- Source:
- Int32.cs
- Source:
- Int32.cs
- Source:
- Int32.cs
Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.
public:
static bool TryParse(System::String ^ s, [Runtime::InteropServices::Out] int % result);
public static bool TryParse (string s, out int result);
public static bool TryParse (string? s, out int result);
static member TryParse : string * int -> bool
Public Shared Function TryParse (s As String, ByRef result As Integer) As Boolean
Parameters
- s
- String
A string containing a number to convert.
- result
- Int32
When this method returns, contains the 32-bit signed integer value equivalent of 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 less than Int32.MinValue or greater than Int32.MaxValue. This parameter is passed uninitialized; any value originally supplied in result
will be overwritten.
Returns
true
if s
was converted successfully; otherwise, false
.
Examples
The following example calls the Int32.TryParse(String, Int32) method with a number of different string values.
using namespace System;
void TryToParse(String^ value)
{
Int32 number;
bool result = Int32::TryParse(value, number);
if (result) {
Console::WriteLine("Converted '{0}' to {1}.", value, number);
}
else {
if (value == nullptr) value = "";
Console::WriteLine("Attempted conversion of '{0}' failed.", value);
}
}
void main()
{
TryToParse(nullptr);
TryToParse("160519");
TryToParse("9432.0");
TryToParse("16,667");
TryToParse(" -322 ");
TryToParse("+4302");
TryToParse("(100);");
TryToParse("01FA");
}
// The example displays the following output:
// Attempted conversion of '' failed.
// Converted '160519' to 160519.
// Attempted conversion of '9432.0' failed.
// Attempted conversion of '16,667' failed.
// Converted ' -322 ' to -322.
// Converted '+4302' to 4302.
// Attempted conversion of '(100);' failed.
// Attempted conversion of '01FA' failed.
using System;
public class Example
{
public static void Main()
{
string[] values = { null, "160519", "9432.0", "16,667",
" -322 ", "+4302", "(100);", "01FA" };
foreach (var value in values)
{
int number;
bool success = int.TryParse(value, out number);
if (success)
{
Console.WriteLine($"Converted '{value}' to {number}.");
}
else
{
Console.WriteLine($"Attempted conversion of '{value ?? "<null>"}' failed.");
}
}
}
}
// The example displays the following output:
// Attempted conversion of '<null>' failed.
// Converted '160519' to 160519.
// Attempted conversion of '9432.0' failed.
// Attempted conversion of '16,667' failed.
// Converted ' -322 ' to -322.
// Converted '+4302' to 4302.
// Attempted conversion of '(100);' failed.
// Attempted conversion of '01FA' failed.
open System
let values =
[ null; "160519"; "9432.0"; "16,667"
" -322 "; "+4302"; "(100);"; "01FA" ]
for value in values do
match Int32.TryParse value with
| true, number ->
printfn $"Converted '{value}' to {number}."
| _ ->
printfn $"""Attempted conversion of '{if isNull value then "<null>" else value}' failed."""
// The example displays the following output:
// Attempted conversion of '<null>' failed.
// Converted '160519' to 160519.
// Attempted conversion of '9432.0' failed.
// Attempted conversion of '16,667' failed.
// Converted ' -322 ' to -322.
// Converted '+4302' to 4302.
// Attempted conversion of '(100);' failed.
// Attempted conversion of '01FA' failed.
Module Example
Public Sub Main()
Dim values() As String = { Nothing, "160519", "9432.0", "16,667",
" -322 ", "+4302", "(100);",
"01FA" }
For Each value In values
Dim number As Integer
Dim success As Boolean = Int32.TryParse(value, number)
If success Then
Console.WriteLine("Converted '{0}' to {1}.", value, number)
Else
Console.WriteLine("Attempted conversion of '{0}' failed.",
If(value ,"<null>"))
End If
Next
End Sub
End Module
' The example displays the following output to the console:
' Attempted conversion of '<null>' failed.
' Converted '160519' to 160519.
' Attempted conversion of '9432.0' failed.
' Attempted conversion of '16,667' failed.
' Converted ' -322 ' to -322.
' Converted '+4302' to 4302.
' Attempted conversion of '(100)' failed.
' Attempted conversion of '01FA' failed.
Some of the strings that the TryParse(String, Int32) method is unable to convert in this example are:
"9432.0". The conversion fails because the string cannot contain a decimal separator; it must contain integral digits only.
"16,667". The conversion fails because the string cannot contain group separators; it must contain integral digits only.
"(100)". The conversion fails because the string cannot contain a negative sign other than the one defined by the current culture's NumberFormatInfo.NegativeSign and NumberFormatInfo.NumberNegativePattern properties.
"01FA". The conversion fails because the string cannot contain hexadecimal digits; it must contain decimal digits only.
Remarks
The TryParse method is like the Parse method, except the TryParse method does not throw an exception if the conversion fails. It eliminates the need to use exception handling to test for a FormatException in the event that s
is invalid and cannot be successfully parsed.
The s
parameter contains a number of the form:
[ws][sign]digits[ws]
Items in square brackets ([ and ]) are optional. The following table describes each element.
Element | Description |
---|---|
ws | Optional white space. |
sign | An optional sign. |
digits | A sequence of digits ranging from 0 to 9. |
The s
parameter is interpreted using the NumberStyles.Integer style. In addition to the decimal digits, only leading and trailing spaces together with a leading sign are allowed. To explicitly define the style elements together with the culture-specific formatting information that can be present in s
, use the Int32.TryParse(String, NumberStyles, IFormatProvider, Int32) method.
The s
parameter is parsed using the formatting information in a NumberFormatInfo object initialized for the current system culture. For more information, see CurrentInfo.
This overload of the TryParse method interprets all digits in the s
parameter as decimal digits. To parse the string representation of a hexadecimal number, call the Int32.TryParse(String, NumberStyles, IFormatProvider, Int32) overload.
See also
- Parse(String)
- ToString()
- Parsing Numeric Strings in .NET
- Sample: .NET Core WinForms Formatting Utility (C#)
- Sample: .NET Core WinForms Formatting Utility (Visual Basic)
Applies to
TryParse(ReadOnlySpan<Byte>, IFormatProvider, Int32)
- Source:
- Int32.cs
- Source:
- Int32.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] int % result) = IUtf8SpanParsable<int>::TryParse;
public static bool TryParse (ReadOnlySpan<byte> utf8Text, IFormatProvider? provider, out int result);
static member TryParse : ReadOnlySpan<byte> * IFormatProvider * int -> bool
Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), provider As IFormatProvider, ByRef result As Integer) 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
- Int32
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>, IFormatProvider, Int32)
- Source:
- Int32.cs
- Source:
- Int32.cs
- Source:
- Int32.cs
Tries to parse a span of characters into a value.
public:
static bool TryParse(ReadOnlySpan<char> s, IFormatProvider ^ provider, [Runtime::InteropServices::Out] int % result) = ISpanParsable<int>::TryParse;
public static bool TryParse (ReadOnlySpan<char> s, IFormatProvider? provider, out int result);
static member TryParse : ReadOnlySpan<char> * IFormatProvider * int -> bool
Public Shared Function TryParse (s As ReadOnlySpan(Of Char), provider As IFormatProvider, ByRef result As Integer) 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
- Int32
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, Int32)
- Source:
- Int32.cs
- Source:
- Int32.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] int % result) = System::Numerics::INumberBase<int>::TryParse;
public static bool TryParse (ReadOnlySpan<byte> utf8Text, System.Globalization.NumberStyles style, IFormatProvider? provider, out int result);
static member TryParse : ReadOnlySpan<byte> * System.Globalization.NumberStyles * IFormatProvider * int -> bool
Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), style As NumberStyles, provider As IFormatProvider, ByRef result As Integer) 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
- Int32
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>, Int32)
- Source:
- Int32.cs
- Source:
- Int32.cs
Tries to convert a UTF-8 character span containing the string representation of a number to its 32-bit signed integer equivalent.
public:
static bool TryParse(ReadOnlySpan<System::Byte> utf8Text, [Runtime::InteropServices::Out] int % result);
public static bool TryParse (ReadOnlySpan<byte> utf8Text, out int result);
static member TryParse : ReadOnlySpan<byte> * int -> bool
Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), ByRef result As Integer) As Boolean
Parameters
- utf8Text
- ReadOnlySpan<Byte>
A span containing the UTF-8 characters representing the number to convert.
- result
- Int32
When this method returns, contains the 32-bit signed 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, Int32)
- Source:
- Int32.cs
- Source:
- Int32.cs
- Source:
- Int32.cs
Converts the span representation of a number in a specified style and culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.
public:
static bool TryParse(ReadOnlySpan<char> s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] int % result);
public:
static bool TryParse(ReadOnlySpan<char> s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] int % result) = System::Numerics::INumberBase<int>::TryParse;
public static bool TryParse (ReadOnlySpan<char> s, System.Globalization.NumberStyles style, IFormatProvider? provider, out int result);
public static bool TryParse (ReadOnlySpan<char> s, System.Globalization.NumberStyles style, IFormatProvider provider, out int result);
static member TryParse : ReadOnlySpan<char> * System.Globalization.NumberStyles * IFormatProvider * int -> bool
Public Shared Function TryParse (s As ReadOnlySpan(Of Char), style As NumberStyles, provider As IFormatProvider, ByRef result As Integer) As Boolean
Parameters
- s
- ReadOnlySpan<Char>
A span containing the characters that represent the number to convert. The span is interpreted using the style specified by style
.
- style
- NumberStyles
A bitwise combination of enumeration values that indicates the style elements that can be present in s
. A typical value to specify is Integer.
- provider
- IFormatProvider
An object that supplies culture-specific formatting information about s
.
- result
- Int32
When this method returns, contains the 32-bit signed integer value equivalent of 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 less than Int32.MinValue or greater than Int32.MaxValue. This parameter is passed uninitialized; any value originally supplied in result
will be overwritten.
Returns
true
if s
was converted successfully; otherwise, false
.
Applies to
TryParse(String, NumberStyles, IFormatProvider, Int32)
- Source:
- Int32.cs
- Source:
- Int32.cs
- Source:
- Int32.cs
Converts the string representation of a number in a specified style and culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.
public:
static bool TryParse(System::String ^ s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] int % result);
public:
static bool TryParse(System::String ^ s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] int % result) = System::Numerics::INumberBase<int>::TryParse;
public static bool TryParse (string s, System.Globalization.NumberStyles style, IFormatProvider provider, out int result);
public static bool TryParse (string? s, System.Globalization.NumberStyles style, IFormatProvider? provider, out int result);
static member TryParse : string * System.Globalization.NumberStyles * IFormatProvider * int -> bool
Public Shared Function TryParse (s As String, style As NumberStyles, provider As IFormatProvider, ByRef result As Integer) As Boolean
Parameters
- s
- String
A string containing a number to convert. The string is interpreted using the style specified by style
.
- style
- NumberStyles
A bitwise combination of enumeration values that indicates the style elements that can be present in s
. A typical value to specify is Integer.
- provider
- IFormatProvider
An object that supplies culture-specific formatting information about s
.
- result
- Int32
When this method returns, contains the 32-bit signed integer value equivalent of 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 less than Int32.MinValue or greater than Int32.MaxValue. This parameter is passed uninitialized; any value originally supplied in result
will be overwritten.
Returns
true
if s
was converted successfully; otherwise, false
.
Exceptions
style
is not a NumberStyles value.
-or-
style
is not a combination of AllowHexSpecifier and HexNumber values.
Examples
The following example calls the Int32.TryParse(String, NumberStyles, IFormatProvider, Int32) method with a number of different string and NumberStyles values.
using namespace System;
using namespace System::Globalization;
void CallTryParse(String^ stringToConvert, NumberStyles styles)
{
Int32 number;
CultureInfo^ provider;
// If currency symbol is allowed, use en-US culture.
if (((Int32) (styles & NumberStyles::AllowCurrencySymbol)) > 0)
provider = gcnew CultureInfo("en-US");
else
provider = CultureInfo::InvariantCulture;
bool result = Int32::TryParse(stringToConvert, styles,
provider, number);
if (result)
Console::WriteLine("Converted '{0}' to {1}.", stringToConvert, number);
else
Console::WriteLine("Attempted conversion of '{0}' failed.",
Convert::ToString(stringToConvert));
}
void main()
{
String^ numericString;
NumberStyles styles;
numericString = "106779";
styles = NumberStyles::Integer;
CallTryParse(numericString, styles);
numericString = "-30677";
styles = NumberStyles::None;
CallTryParse(numericString, styles);
styles = NumberStyles::AllowLeadingSign;
CallTryParse(numericString, styles);
numericString = "301677-";
CallTryParse(numericString, styles);
styles = styles | NumberStyles::AllowTrailingSign;
CallTryParse(numericString, styles);
numericString = "$10634";
styles = NumberStyles::Integer;
CallTryParse(numericString, styles);
styles = NumberStyles::Integer | NumberStyles::AllowCurrencySymbol;
CallTryParse(numericString, styles);
numericString = "10345.00";
styles = NumberStyles::Integer | NumberStyles::AllowDecimalPoint;
CallTryParse(numericString, styles);
numericString = "10345.72";
styles = NumberStyles::Integer | NumberStyles::AllowDecimalPoint;
CallTryParse(numericString, styles);
numericString = "22,593";
styles = NumberStyles::Integer | NumberStyles::AllowThousands;
CallTryParse(numericString, styles);
numericString = "12E-01";
styles = NumberStyles::Integer | NumberStyles::AllowExponent;
CallTryParse(numericString, styles);
numericString = "12E03";
CallTryParse(numericString, styles);
numericString = "80c1";
CallTryParse(numericString, NumberStyles::HexNumber);
numericString = "0x80C1";
CallTryParse(numericString, NumberStyles::HexNumber);
Console::ReadLine();
}
// The example displays the following output:
// Converted '106779' to 106779.
// Attempted conversion of '-30677' failed.
// Converted '-30677' to -30677.
// Attempted conversion of '301677-' failed.
// Converted '301677-' to -301677.
// Attempted conversion of '$10634' failed.
// Converted '$10634' to 10634.
// Converted '10345.00' to 10345.
// Attempted conversion of '10345.72' failed.
// Converted '22,593' to 22593.
// Attempted conversion of '12E-01' failed.
// Converted '12E03' to 12000.
// Converted '80c1' to 32961.
// Attempted conversion of '0x80C1' failed.
using System;
using System.Globalization;
public class StringParsing
{
public static void Main()
{
string numericString;
NumberStyles styles;
numericString = "106779";
styles = NumberStyles.Integer;
CallTryParse(numericString, styles);
numericString = "-30677";
styles = NumberStyles.None;
CallTryParse(numericString, styles);
styles = NumberStyles.AllowLeadingSign;
CallTryParse(numericString, styles);
numericString = "301677-";
CallTryParse(numericString, styles);
styles = styles | NumberStyles.AllowTrailingSign;
CallTryParse(numericString, styles);
numericString = "$10634";
styles = NumberStyles.Integer;
CallTryParse(numericString, styles);
styles = NumberStyles.Integer | NumberStyles.AllowCurrencySymbol;
CallTryParse(numericString, styles);
numericString = "10345.00";
styles = NumberStyles.Integer | NumberStyles.AllowDecimalPoint;
CallTryParse(numericString, styles);
numericString = "10345.72";
styles = NumberStyles.Integer | NumberStyles.AllowDecimalPoint;
CallTryParse(numericString, styles);
numericString = "22,593";
styles = NumberStyles.Integer | NumberStyles.AllowThousands;
CallTryParse(numericString, styles);
numericString = "12E-01";
styles = NumberStyles.Integer | NumberStyles.AllowExponent;
CallTryParse(numericString, styles);
numericString = "12E03";
CallTryParse(numericString, styles);
numericString = "80c1";
CallTryParse(numericString, NumberStyles.HexNumber);
numericString = "0x80C1";
CallTryParse(numericString, NumberStyles.HexNumber);
}
private static void CallTryParse(string stringToConvert, NumberStyles styles)
{
CultureInfo provider;
// If currency symbol is allowed, use en-US culture.
if ((styles & NumberStyles.AllowCurrencySymbol) > 0)
provider = new CultureInfo("en-US");
else
provider = CultureInfo.InvariantCulture;
bool success = int.TryParse(stringToConvert, styles,
provider, out int number);
if (success)
Console.WriteLine($"Converted '{stringToConvert}' to {number}.");
else
Console.WriteLine($"Attempted conversion of '{stringToConvert}' failed.");
}
}
// The example displays the following output to the console:
// Converted '106779' to 106779.
// Attempted conversion of '-30677' failed.
// Converted '-30677' to -30677.
// Attempted conversion of '301677-' failed.
// Converted '301677-' to -301677.
// Attempted conversion of '$10634' failed.
// Converted '$10634' to 10634.
// Converted '10345.00' to 10345.
// Attempted conversion of '10345.72' failed.
// Converted '22,593' to 22593.
// Attempted conversion of '12E-01' failed.
// Converted '12E03' to 12000.
// Converted '80c1' to 32961.
// Attempted conversion of '0x80C1' failed.
open System
open System.Globalization
let callTryParse (stringToConvert: string) styles =
let provider =
// If currency symbol is allowed, use en-US culture.
if int (styles &&& NumberStyles.AllowCurrencySymbol) > 0 then
CultureInfo "en-US"
else
CultureInfo.InvariantCulture
match Int32.TryParse(stringToConvert, styles, provider) with
| true, number ->
printfn $"Converted '{stringToConvert}' to {number}."
| _ ->
printfn $"Attempted conversion of '{stringToConvert}' failed."
[<EntryPoint>]
let main _ =
let numericString = "106779"
let styles = NumberStyles.Integer
callTryParse numericString styles
let numericString = "-30677"
let styles = NumberStyles.None
callTryParse numericString styles
let styles = NumberStyles.AllowLeadingSign
callTryParse numericString styles
let numericString = "301677-"
callTryParse numericString styles
let styles = styles ||| NumberStyles.AllowTrailingSign
callTryParse numericString styles
let numericString = "$10634"
let styles = NumberStyles.Integer
callTryParse numericString styles
let styles = NumberStyles.Integer ||| NumberStyles.AllowCurrencySymbol
callTryParse numericString styles
let numericString = "10345.00"
let styles = NumberStyles.Integer ||| NumberStyles.AllowDecimalPoint
callTryParse numericString styles
let numericString = "10345.72"
let styles = NumberStyles.Integer ||| NumberStyles.AllowDecimalPoint
callTryParse numericString styles
let numericString = "22,593"
let styles = NumberStyles.Integer ||| NumberStyles.AllowThousands
callTryParse numericString styles
let numericString = "12E-01"
let styles = NumberStyles.Integer ||| NumberStyles.AllowExponent
callTryParse numericString styles
let numericString = "12E03"
callTryParse numericString styles
let numericString = "80c1"
callTryParse numericString NumberStyles.HexNumber
let numericString = "0x80C1"
callTryParse numericString NumberStyles.HexNumber
0
// The example displays the following output to the console:
// Converted '106779' to 106779.
// Attempted conversion of '-30677' failed.
// Converted '-30677' to -30677.
// Attempted conversion of '301677-' failed.
// Converted '301677-' to -301677.
// Attempted conversion of '$10634' failed.
// Converted '$10634' to 10634.
// Converted '10345.00' to 10345.
// Attempted conversion of '10345.72' failed.
// Converted '22,593' to 22593.
// Attempted conversion of '12E-01' failed.
// Converted '12E03' to 12000.
// Converted '80c1' to 32961.
// Attempted conversion of '0x80C1' failed.
Imports System.Globalization
Module StringParsing
Public Sub Main()
Dim numericString As String
Dim styles As NumberStyles
numericString = "106779"
styles = NumberStyles.Integer
CallTryParse(numericString, styles)
numericString = "-30677"
styles = NumberStyles.None
CallTryParse(numericString, styles)
styles = NumberStyles.AllowLeadingSign
CallTryParse(numericString, styles)
numericString = "301677-"
CallTryParse(numericString, styles)
styles = styles Or NumberStyles.AllowTrailingSign
CallTryParse(numericString, styles)
numericString = "$10634"
styles = NumberStyles.Integer
CallTryParse(numericString, styles)
styles = NumberStyles.Integer Or NumberStyles.AllowCurrencySymbol
CallTryParse(numericString, styles)
numericString = "10345.00"
styles = NumberStyles.Integer Or NumberStyles.AllowDecimalPoint
CallTryParse(numericString, styles)
numericString = "10345.72"
styles = NumberStyles.Integer Or NumberStyles.AllowDecimalPoint
CallTryParse(numericString, styles)
numericString = "22,593"
styles = NumberStyles.Integer Or NumberStyles.AllowThousands
CallTryParse(numericString, styles)
numericString = "12E-01"
styles = NumberStyles.Integer Or NumberStyles.AllowExponent
CallTryParse(numericString, styles)
numericString = "12E03"
CallTryParse(numericString, styles)
numericString = "80c1"
CallTryParse(numericString, NumberStyles.HexNumber)
numericString = "0x80C1"
CallTryParse(numericString, NumberStyles.HexNumber)
End Sub
Private Sub CallTryParse(stringToConvert As String, styles AS NumberStyles)
Dim number As Integer
Dim provider As CultureInfo
' If currency symbol is allowed, use en-US culture.
If CBool(styles And NumberStyles.AllowCurrencySymbol) Then
provider = CultureInfo.CurrentCulture
Else
provider = New CultureInfo("en-US")
End If
Dim result As Boolean = Int32.TryParse(stringToConvert, styles, _
provider, 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 '106779' to 106779.
' Attempted conversion of '-30677' failed.
' Converted '-30677' to -30677.
' Attempted conversion of '301677-' failed.
' Converted '301677-' to -301677.
' Attempted conversion of '$10634' failed.
' Converted '$10634' to 10634.
' Converted '10345.00' to 10345.
' Attempted conversion of '10345.72' failed.
' Converted '22,593' to 22593.
' Attempted conversion of '12E-01' failed.
' Converted '12E03' to 12000.
' Converted '80c1' to 32961.
' Attempted conversion of '0x80C1' failed.
Remarks
The TryParse method is like the Parse method, except the TryParse method does not throw an exception if the conversion fails. It eliminates the need to use exception handling to test for a FormatException in the event that s
is invalid and cannot be parsed successfully.
The style
parameter defines the style elements (such as white space or a positive or negative sign) that are allowed in the s
parameter for the parse operation to succeed. It must be a combination of bit flags from the NumberStyles enumeration. Depending on the value of style
, the s
parameter may include the following elements:
[ws][$][sign][digits,]digits[.fractional_digits][e[sign]digits][ws]
Or, if the style
parameter includes AllowHexSpecifier:
[ws]hexdigits[ws]
Items in square brackets ([ and ]) are optional. The following table describes each element.
Element | Description |
---|---|
ws | Optional white space. White space can appear at the beginning 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. A sign symbol can appear in s if style includes the NumberStyles.AllowLeadingSign or NumberStyles.AllowTrailingSign flags. |
digits | A sequence of digits from 0 through 9. |
, | A culture-specific thousands separator. The thousands 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 notation. 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 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 s in addition to digits |
---|---|
NumberStyles.None | Decimal digits only. |
NumberStyles.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 . |
NumberStyles.AllowExponent | The s parameter can also use exponential notation. If s represents a number in exponential notation, it must represent an integer within the range of the Int32 data type without a non-zero, fractional component. |
NumberStyles.AllowLeadingWhite | The ws element at the beginning of s . |
NumberStyles.AllowTrailingWhite | The ws element at the end of s . |
NumberStyles.AllowLeadingSign | A sign can appear before digits. |
NumberStyles.AllowTrailingSign | A sign can appear after digits. |
NumberStyles.AllowParentheses | The sign element in the form of parentheses enclosing the numeric value. |
NumberStyles.AllowThousands | The thousands separator (,) element. |
NumberStyles.AllowCurrencySymbol | The $ element. |
NumberStyles.Currency | All elements. The s parameter cannot represent a hexadecimal number or a number in exponential notation. |
NumberStyles.Float | The ws element at the beginning or end of s , sign at the beginning of s , and the decimal point (.) symbol. The s parameter can also use exponential notation. |
NumberStyles.Number | The ws, sign, thousands separator (,), and decimal point (.) elements. |
NumberStyles.Any | All styles, except s cannot represent a hexadecimal number. |
If the NumberStyles.AllowHexSpecifier flag is used, s
must be a hexadecimal value without a prefix. For example, "C9AF3" parses successfully, but "0xC9AF3" does not. The only other flags that can be present in style
are NumberStyles.AllowLeadingWhite and NumberStyles.AllowTrailingWhite. (The NumberStyles enumeration has a composite style, NumberStyles.HexNumber, that includes both white space flags.)
The provider
parameter is an IFormatProvider implementation, such as a CultureInfo object or a NumberFormatInfo object, whose GetFormat method returns a NumberFormatInfo object. The NumberFormatInfo object provides culture-specific information about the format of s
. If provider
is null
, the NumberFormatInfo object for the current culture is used.
See also
Applies to
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