Decimal.TryParse 方法

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(ReadOnlySpan<System::Byte> utf8Text, [Runtime::InteropServices::Out] System::Decimal % result);

public static bool TryParse(ReadOnlySpan<byte> utf8Text, out decimal result);

static member TryParse : ReadOnlySpan<byte> * decimal -> bool

Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), ByRef result As Decimal) As Boolean

参数

返回

如果已成功转换 utf8Text，则 true;否则，false。

Source:

Decimal.cs

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(ReadOnlySpan<char> s, [Runtime::InteropServices::Out] System::Decimal % result);

public static bool TryParse(ReadOnlySpan<char> s, out decimal result);

static member TryParse : ReadOnlySpan<char> * decimal -> bool

Public Shared Function TryParse (s As ReadOnlySpan(Of Char), ByRef result As Decimal) As Boolean

参数

返回

如果已成功转换 s，则 true;否则，false。

Source:

Decimal.cs

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(System::String ^ s, [Runtime::InteropServices::Out] System::Decimal % result);

public static bool TryParse(string s, out decimal result);

public static bool TryParse(string? s, out decimal result);

static member TryParse : string * decimal -> bool

Public Shared Function TryParse (s As String, ByRef result As Decimal) As Boolean

参数

返回

如果已成功转换 s，则 true;否则，false。

示例

以下示例使用 Decimal.TryParse(String, Decimal) 方法将数值的字符串表示形式转换为 Decimal 值。 它假定 en-US 是当前区域性。

string value;
decimal number;

// Parse a floating-point value with a thousands separator.
value = "1,643.57";
if (Decimal.TryParse(value, out number))
   Console.WriteLine(number);
else
   Console.WriteLine("Unable to parse '{0}'.", value);

// Parse a floating-point value with a currency symbol and a
// thousands separator.
value = "$1,643.57";
if (Decimal.TryParse(value, out number))
   Console.WriteLine(number);
else
   Console.WriteLine("Unable to parse '{0}'.", value);

// Parse value in exponential notation.
value = "-1.643e6";
if (Decimal.TryParse(value, out number))
   Console.WriteLine(number);
else
   Console.WriteLine("Unable to parse '{0}'.", value);

// Parse a negative integer value.
value = "-1689346178821";
if (Decimal.TryParse(value, out number))
   Console.WriteLine(number);
else
   Console.WriteLine("Unable to parse '{0}'.", value);
// The example displays the following output to the console:
//       1643.57
//       Unable to parse '$1,643.57'.
//       Unable to parse '-1.643e6'.
//       -1689346178821

// Parse a floating-point value with a thousands separator.
let value = "1,643.57"
match Decimal.TryParse value with
| true, number ->
    printfn $"{number}"
| _ ->
    printfn $"Unable to parse '{value}'."

// Parse a floating-point value with a currency symbol and a
// thousands separator.
let value = "$1,643.57"
match Decimal.TryParse value with
| true, number ->
    printfn $"{number}"
| _ -> 
    printfn $"Unable to parse '{value}'."

// Parse value in exponential notation.
let value = "-1.643e6"
match Decimal.TryParse value with
| true, number ->
    printfn $"{number}"
| _ -> 
    printfn $"Unable to parse '{value}'."

// Parse a negative integer value.
let value = "-1689346178821"
match Decimal.TryParse value with
| true, number ->
    printfn $"{number}"
| _ -> 
    printfn $"Unable to parse '{value}'."
// The example displays the following output to the console:
//       1643.57
//       Unable to parse '$1,643.57'.
//       Unable to parse '-1.643e6'.
//       -1689346178821

Dim value As String
Dim number As Decimal

' Parse a floating-point value with a thousands separator.
value = "1,643.57"
If Decimal.TryParse(value, number) Then
   Console.WriteLine(number)
Else
   Console.WriteLine("Unable to parse '{0}'.", value)      
End If   

' Parse a floating-point value with a currency symbol and a 
' thousands separator.
value = "$1,643.57"
If Decimal.TryParse(value, number) Then
   Console.WriteLine(number)  
Else
   Console.WriteLine("Unable to parse '{0}'.", value)   
End If

' Parse value in exponential notation.
value = "-1.643e6"
If Decimal.TryParse(value, number)
   Console.WriteLine(number)
Else
   Console.WriteLine("Unable to parse '{0}'.", value)   
End If

' Parse a negative integer value.
value = "-1689346178821"
If Decimal.TryParse(value, number)
   Console.WriteLine(number)
Else
   Console.WriteLine("Unable to parse '{0}'.", value)   
End If
' The example displays the following output to the console:
'       1643.57
'       Unable to parse '$1,643.57'.
'       Unable to parse '-1.643e6'.
'       -1689346178821

注解

此重载与 Decimal.Parse(String) 方法不同，方法是返回一个布尔值，该值指示分析操作是否成功，而不是返回已分析的数值。 它消除了在 s 无效且无法成功分析的情况下使用异常处理来测试 FormatException 的需要。

参数 s 包含多种形式：

[ws][sign][digits，]digits[.fractional-digits][ws]

方括号 （[ 和 ]） 中的元素是可选的。 下表描述了每个元素。

使用 NumberStyles.Number 样式解释参数 s。 这意味着允许空格和数千个分隔符，但货币符号不是。 若要显式定义可以存在于 s中的元素（如货币符号、千位分隔符和空格），请使用 Decimal.TryParse(String, NumberStyles, IFormatProvider, Decimal) 方法重载。

使用为当前系统区域性初始化的 NumberFormatInfo 对象中的格式信息分析参数 s。 有关详细信息，请参阅 CurrentInfo。 若要使用其他指定区域性的格式设置信息分析字符串，请使用 Decimal.TryParse(String, NumberStyles, IFormatProvider, Decimal) 方法重载。

如有必要，使用舍入到最接近的舍入将 s 的值舍入。

Decimal 对象具有 29 位精度。 如果 s 表示数字超过 29 位，但具有小数部分，并且位于 MaxValue 和 MinValue范围内，则数字将舍入（而不是截断）到 29 位（使用舍入到最接近）。

如果在分析操作期间遇到 s 参数中的分隔符，并且适用的货币或数字小数和组分隔符相同，则分析操作假定分隔符是小数分隔符，而不是组分隔符。 有关分隔符的详细信息，请参阅 CurrencyDecimalSeparator、NumberDecimalSeparator、CurrencyGroupSeparator和 NumberGroupSeparator。

另请参阅

• Parse
• ToString()
• 分析 .NET 中的数值字符串

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(ReadOnlySpan<System::Byte> utf8Text, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::Decimal % result) = IUtf8SpanParsable<System::Decimal>::TryParse;

public static bool TryParse(ReadOnlySpan<byte> utf8Text, IFormatProvider? provider, out decimal result);

static member TryParse : ReadOnlySpan<byte> * IFormatProvider * decimal -> bool

Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), provider As IFormatProvider, ByRef result As Decimal) As Boolean

参数

返回

如果已成功分析 utf8Text，则 true;否则，false。

Source:

Decimal.cs

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(ReadOnlySpan<char> s, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::Decimal % result) = ISpanParsable<System::Decimal>::TryParse;

public static bool TryParse(ReadOnlySpan<char> s, IFormatProvider? provider, out decimal result);

static member TryParse : ReadOnlySpan<char> * IFormatProvider * decimal -> bool

Public Shared Function TryParse (s As ReadOnlySpan(Of Char), provider As IFormatProvider, ByRef result As Decimal) As Boolean

参数

返回

如果已成功分析 s，则 true;否则，false。

Source:

Decimal.cs

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(System::String ^ s, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::Decimal % result) = IParsable<System::Decimal>::TryParse;

public static bool TryParse(string? s, IFormatProvider? provider, out decimal result);

static member TryParse : string * IFormatProvider * decimal -> bool

Public Shared Function TryParse (s As String, provider As IFormatProvider, ByRef result As Decimal) As Boolean

参数

返回

如果已成功分析 s，则 true;否则，false。

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(ReadOnlySpan<System::Byte> utf8Text, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::Decimal % result) = System::Numerics::INumberBase<System::Decimal>::TryParse;

public static bool TryParse(ReadOnlySpan<byte> utf8Text, System.Globalization.NumberStyles style, IFormatProvider? provider, out decimal result);

static member TryParse : ReadOnlySpan<byte> * System.Globalization.NumberStyles * IFormatProvider * decimal -> bool

Public Shared Function TryParse (utf8Text As ReadOnlySpan(Of Byte), style As NumberStyles, provider As IFormatProvider, ByRef result As Decimal) As Boolean

参数

返回

如果已成功分析 utf8Text，则 true;否则，false。

Source:

Decimal.cs

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(ReadOnlySpan<char> s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::Decimal % result) = System::Numerics::INumberBase<System::Decimal>::TryParse;

public:
 static bool TryParse(ReadOnlySpan<char> s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::Decimal % result);

public static bool TryParse(ReadOnlySpan<char> s, System.Globalization.NumberStyles style, IFormatProvider? provider, out decimal result);

public static bool TryParse(ReadOnlySpan<char> s, System.Globalization.NumberStyles style, IFormatProvider provider, out decimal result);

static member TryParse : ReadOnlySpan<char> * System.Globalization.NumberStyles * IFormatProvider * decimal -> bool

Public Shared Function TryParse (s As ReadOnlySpan(Of Char), style As NumberStyles, provider As IFormatProvider, ByRef result As Decimal) As Boolean

参数

返回

如果已成功转换 s，则 true;否则，false。

Source:

Decimal.cs

Source:

Decimal.cs

Source:

Decimal.cs

public:
 static bool TryParse(System::String ^ s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::Decimal % result);

public:
 static bool TryParse(System::String ^ s, System::Globalization::NumberStyles style, IFormatProvider ^ provider, [Runtime::InteropServices::Out] System::Decimal % result) = System::Numerics::INumberBase<System::Decimal>::TryParse;

public static bool TryParse(string s, System.Globalization.NumberStyles style, IFormatProvider provider, out decimal result);

public static bool TryParse(string? s, System.Globalization.NumberStyles style, IFormatProvider? provider, out decimal result);

static member TryParse : string * System.Globalization.NumberStyles * IFormatProvider * decimal -> bool

Public Shared Function TryParse (s As String, style As NumberStyles, provider As IFormatProvider, ByRef result As Decimal) As Boolean

参数

返回

如果已成功转换 s，则 true;否则，false。

例外

示例

下面的示例演示如何使用 TryParse(String, NumberStyles, IFormatProvider, Decimal) 方法分析具有特定样式的数字的字符串表示形式，并使用特定区域性的约定进行格式化。

string value;
NumberStyles style;
CultureInfo culture;
decimal number;

// Parse currency value using en-GB culture.
value = "£1,097.63";
style = NumberStyles.Number | NumberStyles.AllowCurrencySymbol;
culture = CultureInfo.CreateSpecificCulture("en-GB");
if (Decimal.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 (Decimal.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 (Decimal.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 (Decimal.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 Decimal.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 Decimal.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 Decimal.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 Decimal.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 Decimal

' Parse currency value using en-GB culture.
value = "£1,097.63"
style = NumberStyles.Number Or NumberStyles.AllowCurrencySymbol
culture = CultureInfo.CreateSpecificCulture("en-GB")
If Decimal.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 Decimal.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 Decimal.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 Decimal.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'.

注解

此重载与 Decimal.Parse(String, NumberStyles, IFormatProvider) 方法不同，方法是返回一个布尔值，该值指示分析操作是否成功，而不是返回已分析的数值。 它消除了在 s 无效且无法成功分析的情况下使用异常处理来测试 FormatException 的需要。

style 参数定义 s 参数允许的格式，以便分析操作成功。 它必须是 NumberStyles 枚举中的位标志的组合。 不支持以下 NumberStyles 成员：

• NumberStyles.AllowHexSpecifier

• NumberStyles.HexNumber

根据样式的值，s 参数可能包括以下元素：

[ws][$][sign][digits，]digits[.fractional-digits][e[sign]digits][ws]

方括号 （[ 和 ]） 中的元素是可选的。 下表描述了每个元素。

style 参数指定 s 参数的允许格式，并且可以是一个或多个使用按位 OR 运算组合的 NumberStyles 枚举常量。 如果 style 为 null，则使用 NumberStyles.Number 样式解释 s。

provider 参数是 IFormatProvider 实现，如 NumberFormatInfo 或 CultureInfo 对象。 provider 参数提供分析中使用的区域性特定信息。 如果 providernull，则使用线程当前区域性。

Decimal 对象具有 29 位精度。 如果 s 表示数字超过 29 位，但具有小数部分，并且位于 MaxValue 和 MinValue范围内，则数字将舍入（而不是截断）到 29 位（使用舍入到最接近）。

如果在分析操作期间 s 参数中遇到分隔符，并且适用的货币或数字小数和组分隔符相同，则分析操作假定分隔符是小数分隔符，而不是组分隔符。 有关分隔符的详细信息，请参阅 CurrencyDecimalSeparator、NumberDecimalSeparator、CurrencyGroupSeparator和 NumberGroupSeparator。

另请参阅

• Parse
• ToString()
• 分析 .NET 中的数值字符串