Double::TryParse Method (String, Double%)

Converts the string representation of a number to its double-precision floating-point number equivalent. A return value indicates whether the conversion succeeded or failed.

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

public:
static bool TryParse(
	String^ s, 
	[OutAttribute] double% result
)

Parameters

s
Type: System::String

A string containing a number to convert.

result
Type: System::Double%

When this method returns, contains the double-precision floating-point number equivalent of the s parameter, if the conversion succeeded, or zero if the conversion failed. The conversion fails if the s parameter is nullptr or String::Empty, is not a number in a valid format, or represents a number less than MinValue or greater than MaxValue. This parameter is passed uninitialized.

Return Value

Type: System::Boolean
true if s was converted successfully; otherwise, false.

This overload differs from the Double::Parse(String) method by returning a Boolean value that indicates whether the parse operation succeeded instead of returning the parsed numeric value. 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 can contain the current culture's NumberFormatInfo::PositiveInfinitySymbol, NumberFormatInfo::NegativeInfinitySymbol, NumberFormatInfo::NaNSymbol (the string comparison is case-sensitive), or a string of the form:

[ws][sign][integral-digits,]integral-digits[.[fractional-digits]][e[sign]exponential-digits][ws]

Elements in square brackets are optional. The following table describes each element.

Element

Description

ws

A series of white-space characters.

sign

A negative sign or positive sign symbol.

integral-digits

A series of numeric characters ranging from 0 to 9 that specify the integral part of the number. Integral-digits can be absent if there are fractional-digits.

,

A culture-specific group separator symbol.

.

A culture-specific decimal point symbol.

fractional-digits

A series of numeric characters ranging from 0 to 9 that specify the fractional part of the number.

E

An uppercase or lowercase character 'e', that indicates exponential (scientific) notation.

exponential-digits

A series of numeric characters ranging from 0 to 9 that specify an exponent.

For more information about numeric formats, see Formatting Types in the .NET Framework.

The s parameter is interpreted by using a combination of the NumberStyles::Float and NumberStyles::AllowThousands flags. This means that white space and thousands separators are allowed but currency symbols are not. To explicitly define the elements (such as currency symbols, thousands separators, and white space) that can be present in s, use the Double::TryParse(String, NumberStyles, IFormatProvider, Double%) method overload.

The s parameter is parsed using the formatting information in a NumberFormatInfo object that is initialized for the current system culture. For more information, see NumberFormatInfo::CurrentInfo. To parse a string using the formatting information of some other specified culture, use the Double::TryParse(String, NumberStyles, IFormatProvider, Double%) method overload.

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 MinValue or MaxValue throws an OverflowException, as the following example illustrates.

No code example is currently available or this language may not be supported.

If a separator is encountered in the s parameter during a parse operation, and the 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.

The following example uses the TryParse(String, Double%) method to convert the string representations of numeric values to Double values. It assumes that en-US is the current culture.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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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