Converts the string representation of a number in a specified style and culture-specific format to its double-precision floating-point number 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] double % result);public:
static bool TryParse(System::String ^ s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] double % result) = System::Numerics::INumberBase<double>::TryParse;public static bool TryParse(string s, System.Globalization.NumberStyles style, IFormatProvider provider, out double result);public static bool TryParse(string? s, System.Globalization.NumberStyles style, IFormatProvider? provider, out double result);static member TryParse : string * System.Globalization.NumberStyles * IFormatProvider * double -> boolPublic Shared Function TryParse (s As String, style As NumberStyles, provider As IFormatProvider, ByRef result As Double) As BooleanA string containing a number to convert.
When this method returns, contains a double-precision floating-point number equivalent of the numeric value or symbol 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 is not in a format compliant with style, or if style is not a valid combination of NumberStyles enumeration constants. It also fails on .NET Framework or .NET Core 2.2 and earlier versions if s represents a number less than SByte.MinValue or greater than SByte.MaxValue. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.
true if s was converted successfully; otherwise, false.
The following example demonstrates the use of the Double.TryParse(String, NumberStyles, IFormatProvider, Double) method to parse the string representation of numbers that have a particular style and are formatted using the conventions of a particular culture.
string value;
NumberStyles style;
CultureInfo culture;
double number;
// Parse currency value using en-GB culture.
value = "£1,097.63";
style = NumberStyles.Number | NumberStyles.AllowCurrencySymbol;
culture = CultureInfo.CreateSpecificCulture("en-GB");
if (Double.TryParse(value, style, culture, out number))
Console.WriteLine("Converted '{0}' to {1}.", value, number);
else
Console.WriteLine("Unable to convert '{0}'.", value);
// Displays:
// Converted '£1,097.63' to 1097.63.
value = "1345,978";
style = NumberStyles.AllowDecimalPoint;
culture = CultureInfo.CreateSpecificCulture("fr-FR");
if (Double.TryParse(value, style, culture, out number))
Console.WriteLine("Converted '{0}' to {1}.", value, number);
else
Console.WriteLine("Unable to convert '{0}'.", value);
// Displays:
// Converted '1345,978' to 1345.978.
value = "1.345,978";
style = NumberStyles.AllowDecimalPoint | NumberStyles.AllowThousands;
culture = CultureInfo.CreateSpecificCulture("es-ES");
if (Double.TryParse(value, style, culture, out number))
Console.WriteLine("Converted '{0}' to {1}.", value, number);
else
Console.WriteLine("Unable to convert '{0}'.", value);
// Displays:
// Converted '1.345,978' to 1345.978.
value = "1 345,978";
if (Double.TryParse(value, style, culture, out number))
Console.WriteLine("Converted '{0}' to {1}.", value, number);
else
Console.WriteLine("Unable to convert '{0}'.", value);
// Displays:
// Unable to convert '1 345,978'.
// Parse currency value using en-GB culture.
let value = "£1,097.63"
let style = NumberStyles.Number ||| NumberStyles.AllowCurrencySymbol
let culture = CultureInfo.CreateSpecificCulture "en-GB"
match Double.TryParse(value, style, culture) with
| true, number ->
printfn $"Converted '{value}' to {number}."
| _ ->
printfn $"Unable to convert '{value}'."
// Displays:
// Converted '£1,097.63' to 1097.63.
let value = "1345,978"
let style = NumberStyles.AllowDecimalPoint
let culture = CultureInfo.CreateSpecificCulture "fr-FR"
match Double.TryParse(value, style, culture) with
| true, number ->
printfn $"Converted '{value}' to {number}."
| _ ->
printfn $"Unable to convert '{value}'."
// Displays:
// Converted '1345,978' to 1345.978.
let value = "1.345,978"
let style = NumberStyles.AllowDecimalPoint ||| NumberStyles.AllowThousands
let culture = CultureInfo.CreateSpecificCulture("es-ES")
match Double.TryParse(value, style, culture) with
| true, number ->
printfn $"Converted '{value}' to {number}."
| _ ->
printfn $"Unable to convert '{value}'."
// Displays:
// Converted '1.345,978' to 1345.978.
let value = "1 345,978"
match Double.TryParse(value, style, culture) with
| true, number ->
printfn $"Converted '{value}' to {number}."
| _ ->
printfn $"Unable to convert '{value}'."
// Displays:
// Unable to convert '1 345,978'.
Dim value As String
Dim style As NumberStyles
Dim culture As CultureInfo
Dim number As Double
' Parse currency value using en-GB culture.
value = "£1,097.63"
style = NumberStyles.Number Or NumberStyles.AllowCurrencySymbol
culture = CultureInfo.CreateSpecificCulture("en-GB")
If Double.TryParse(value, style, culture, number) Then
Console.WriteLine("Converted '{0}' to {1}.", value, number)
Else
Console.WriteLine("Unable to convert '{0}'.", value)
End If
' Displays:
' Converted '£1,097.63' to 1097.63.
value = "1345,978"
style = NumberStyles.AllowDecimalPoint
culture = CultureInfo.CreateSpecificCulture("fr-FR")
If Double.TryParse(value, style, culture, number) Then
Console.WriteLine("Converted '{0}' to {1}.", value, number)
Else
Console.WriteLine("Unable to convert '{0}'.", value)
End If
' Displays:
' Converted '1345,978' to 1345.978.
value = "1.345,978"
style = NumberStyles.AllowDecimalPoint Or NumberStyles.AllowThousands
culture = CultureInfo.CreateSpecificCulture("es-ES")
If Double.TryParse(value, style, culture, number) Then
Console.WriteLine("Converted '{0}' to {1}.", value, number)
Else
Console.WriteLine("Unable to convert '{0}'.", value)
End If
' Displays:
' Converted '1.345,978' to 1345.978.
value = "1 345,978"
If Double.TryParse(value, style, culture, number) Then
Console.WriteLine("Converted '{0}' to {1}.", value, number)
Else
Console.WriteLine("Unable to convert '{0}'.", value)
End If
' Displays:
' Unable to convert '1 345,978'.
In .NET Core 3.0 and later, values that are too large to represent are rounded to PositiveInfinity or NegativeInfinity as required by the IEEE 754 specification. In prior versions, including .NET Framework, parsing a value that was too large to represent resulted in failure.
The TryParse method is like the Parse(String, NumberStyles, IFormatProvider) method, except this method does not throw an exception if the conversion fails. If the conversion succeeds, the return value is true and the result parameter is set to the outcome of the conversion. If the conversion fails, the return value is false and the result parameter is set to zero. This 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 style parameter defines the allowable format of the s parameter for the parse operation to succeed. It must be a combination of bit flags from the NumberStyles enumeration. The following NumberStyles members are not supported:
The s parameter can contain NumberFormatInfo.PositiveInfinitySymbol, NumberFormatInfo.NegativeInfinitySymbol, or NumberFormatInfo.NaNSymbol for the culture indicated by provider. In addition, depending on the value of style, the s parameter may include the following elements:
[ws] [$] [sign][integral-digits,]integral-digits[.fractional-digits][e[sign]exponential-digits][ws]
Elements in square brackets ([ and ]) are optional. The following table describes each element.
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 digits only (which corresponds to the NumberStyles.None style) always parses successfully if it is in the range of the Double type. The remaining System.Globalization.NumberStyles members control elements that may be but are not required to be present in the input string. The following table indicates how individual NumberStyles flags affect the elements that may be present in s.
s parameter can also use exponential notation. This flag by itself supports values in the form integral-digitsEexponential-digits; additional flags are needed to successfully parse strings in exponential notation with such elements as positive or negative signs and decimal point symbols. AllowLeadingWhite The ws element at the beginning of s. AllowTrailingWhite The ws element at the end of s. AllowLeadingSign The sign element at the beginning of s. AllowTrailingSign The sign element at the end of s. AllowParentheses The sign element in the form of parentheses enclosing the numeric value. AllowThousands The , element. AllowCurrencySymbol The $ element. Currency All. The s parameter cannot represent a hexadecimal number or a number in exponential notation. Float The ws element at the beginning or end of s, sign at the beginning of s, and the . symbol. The s parameter can also use exponential notation. Number The ws, sign, thousands separator (,), and decimal point (.) elements. Any All styles, except s cannot represent a hexadecimal number.
The provider parameter is a IFormatProvider implementation, such as a NumberFormatInfo or CultureInfo object. The provider parameter supplies culture-specific information used in parsing. If provider is null or a NumberFormatInfo object cannot be obtained, the format information for the current culture is used.
The conversion fails if the s parameter is null or not a numeric value, the provider parameter does not yield a NumberFormatInfo object, or the style parameter is not a combination of bit flags from the NumberStyles enumeration.
Ordinarily, if you pass the Double.TryParse method a string that is created by calling the Double.ToString method, the original Double value is returned. However, because of a loss of precision, the values may not be equal. In addition, attempting to parse the string representation of either Double.MinValue or Double.MaxValue fails to round-trip. On .NET Framework and .NET Core 2.2 and previous versions, it throws an OverflowException. On .NET Core 3.0 and later versions, it returns Double.NegativeInfinity if you attempt to parse MinValue or Double.PositiveInfinity if you attempt to parse MaxValue. The following example provides an illustration.
using System;
public class Example
{
public static void Main()
{
string value;
double number;
value = Double.MinValue.ToString();
if (Double.TryParse(value, out number))
Console.WriteLine(number);
else
Console.WriteLine("{0} is outside the range of a Double.",
value);
value = Double.MaxValue.ToString();
if (Double.TryParse(value, out number))
Console.WriteLine(number);
else
Console.WriteLine("{0} is outside the range of a Double.",
value);
}
}
// The example displays the following output:
// -1.79769313486232E+308 is outside the range of the Double type.
// 1.79769313486232E+308 is outside the range of the Double type.
open System
[<EntryPoint>]
let main _ =
let value = string Double.MinValue
match Double.TryParse value with
| true, number ->
printfn $"{number}"
| _ ->
printfn $"{value} is outside the range of a Double."
let value = string Double.MaxValue
match Double.TryParse value with
| true, number ->
printfn $"{number}"
| _ ->
printfn $"{value} is outside the range of a Double."
0
// The example displays the following output:
// -1.79769313486232E+308 is outside the range of the Double type.
// 1.79769313486232E+308 is outside the range of the Double type.
Module Example
Public Sub Main()
Dim value As String
Dim number As Double
value = Double.MinValue.ToString()
If Double.TryParse(value, number) Then
Console.WriteLine(number)
Else
Console.WriteLine("{0} is outside the range of a Double.", _
value)
End If
value = Double.MaxValue.ToString()
If Double.TryParse(value, number) Then
Console.WriteLine(number)
Else
Console.WriteLine("{0} is outside the range of a Double.", _
value)
End If
End Sub
End Module
' The example displays the following output:
' -1.79769313486232E+308 is outside the range of the Double type.
' 1.79769313486232E+308 is outside the range of the Double type.
On .NET Framework and .NET Core 2.2 and earlier versions, if s is out of range of the Double data type, the Double.TryParse(String, NumberStyles, IFormatProvider, Double) method throws an OverflowException.
On .NET Core 3.0 and later versions, no exception is thrown when s is out of range of the Double data type. In most cases, the Double.TryParse(String, NumberStyles, IFormatProvider, Double) method calculates a result of Double.PositiveInfinity or Double.NegativeInfinity. However, there is a small set of values that are considered to be closer to the maximum or minimum values of Double than to positive or negative infinity. In those cases, the method calculates a result of Double.MaxValue or Double.MinValue.
If a separator is encountered in the s parameter during a parse operation, and the applicable currency or number decimal and group separators are the same, the parse operation assumes that the separator is a decimal separator rather than a group separator. For more information about separators, see CurrencyDecimalSeparator, NumberDecimalSeparator, CurrencyGroupSeparator, and NumberGroupSeparator.
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4