SByte.Parse Method (String, NumberStyles, IFormatProvider)
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Converts the string representation of a number that is in a specified style and culture-specific format to its 8-bit signed equivalent.
This API is not CLS-compliant. The CLS-compliant alternative is Parse(String, NumberStyles, IFormatProvider).
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
<CLSCompliantAttribute(False)> _
Public Shared Function Parse ( _
s As String, _
style As NumberStyles, _
provider As IFormatProvider _
) As SByte
[CLSCompliantAttribute(false)]
public static sbyte Parse(
string s,
NumberStyles style,
IFormatProvider provider
)
Parameters
- s
Type: System.String
A string that contains the number to convert. The string is interpreted by using the style specified by style.
- style
Type: System.Globalization.NumberStyles
A bitwise combination of the enumeration values that indicates the style elements that can be present in s. A typical value to specify is NumberStyles.Integer.
- provider
Type: System.IFormatProvider
An object that supplies culture-specific formatting information about s. If provider is nulla null reference (Nothing in Visual Basic), the thread current culture is used.
Return Value
Type: System.SByte
An 8-bit signed byte value that is equivalent to the number specified in the s parameter.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentException | style is not a NumberStyles value. -or- style is not a combination of AllowHexSpecifier and HexNumber. |
| ArgumentNullException | s is nulla null reference (Nothing in Visual Basic). |
| FormatException | s is not in a format that is compliant with style. |
| OverflowException | s represents a number that is less than MinValue or greater than MaxValue. -or- s includes non-zero, fractional digits. |
Remarks
The style parameter defines the style elements (such as white space or the positive or negative sign symbol) 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[.fractional_digits][E[sign]exponential_digits][ws]
If style includes AllowHexSpecifier, the s parameter may include the following elements:
[ws]hexdigits[ws]
Elements 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, and it can appear 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 NumberFormatInfo.CurrencyPositivePattern property of the current culture. The current culture's currency symbol can appear in s if style includes the NumberStyles.AllowCurrencySymbol flag. |
sign |
An optional sign. The sign can appear at the beginning of s if style includes the NumberStyles.AllowLeadingSign flag, and it can appear 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. |
digits |
A sequence of digits from 0 through 9. |
. |
A culture-specific decimal point symbol. The current culture's decimal point symbol can appear in s if style includes the NumberStyles.AllowDecimalPoint flag. |
fractional_digits |
One or more occurrences of the digit 0-9 if style includes the NumberStyles.AllowExponent flag, or one or more occurrences of the digit 0 if it does not. 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. |
A string with decimal digits only (which corresponds to the NumberStyles.None style) 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 s in addition to digits |
|---|---|
Decimal digits only. |
|
The decimal point (.) and fractional_digits elements. However, if style does not include the NumberStyles.AllowExponent flag, fractional_digits must consist of only one or more 0 digits; otherwise, an OverflowException is thrown. |
|
The "e" or "E" character, which indicates exponential notation, along with exponential_digits. |
|
The ws element at the beginning of s. |
|
The ws element at the end of s. |
|
A positive sign before digits. |
|
A positive sign after digits. |
|
Parentheses before and after digits to indicate a negative value. |
|
The group separator (,) element. Although the group separator can appear in s, it must be preceded by only one or more 0 digits. |
|
The currency ($) element. |
If the NumberStyles.AllowHexSpecifier flag is used, s must be a hexadecimal value. The only other flags that can be combined with it are NumberStyles.AllowLeadingWhite and NumberStyles.AllowTrailingWhite. (The NumberStyles enumeration includes a composite number style, NumberStyles.HexNumber, that includes both white-space flags.)
.gif "Note") Note: |
|---|
If the s parameter 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 parse operation to throw an exception. |
If s represents a hexadecimal number, the Parse(String, NumberStyles) method interprets the high-order bit of the byte as a sign bit.
The provider parameter is an IFormatProvider implementation whose GetFormat method returns a NumberFormatInfo object that provides culture-specific information about the format of s. There are three ways to use the provider parameter to supply custom formatting information to the parse operation:
You can pass the actual NumberFormatInfo object that provides formatting information. (Its implementation of GetFormat simply returns itself.)
You can pass a CultureInfo object that specifies the culture whose formatting is to be used. Its NumberFormat property provides formatting information.
You can pass a custom IFormatProvider implementation. Its GetFormat method must instantiate and return the NumberFormatInfo object that provides formatting information.
If provider is nulla null reference (Nothing in Visual Basic), the NumberFormatInfo object for the current culture is used.
Examples
The following example illustrates the use of the Parse(String, NumberStyles, IFormatProvider) method to convert various string representations of numbers to signed integer values.
Imports System.Globalization
Module Example
Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
Dim byteString As String
byteString = " 123"
ParseString(outputBlock, byteString, NumberStyles.None)
ParseString(outputBlock, byteString, NumberStyles.Integer)
byteString = "3A"
ParseString(outputBlock, byteString, NumberStyles.AllowHexSpecifier)
byteString = "21"
ParseString(outputBlock, byteString, NumberStyles.Integer)
ParseString(outputBlock, byteString, NumberStyles.AllowHexSpecifier)
byteString = "-22"
ParseString(outputBlock, byteString, NumberStyles.Integer)
ParseString(outputBlock, byteString, NumberStyles.AllowParentheses)
byteString = "(45)"
ParseString(outputBlock, byteString, NumberStyles.AllowParentheses)
byteString = "000,000,056"
ParseString(outputBlock, byteString, NumberStyles.Integer)
ParseString(outputBlock, byteString, NumberStyles.Integer Or NumberStyles.AllowThousands)
End Sub
Private Sub ParseString(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal value As String, ByVal style As NumberStyles)
Dim number As SByte
Try
number = SByte.Parse(value, style, NumberFormatInfo.CurrentInfo)
outputBlock.Text += String.Format("SByte.Parse(""{0}"", {1})) = {2}", value, style.ToString, number) & vbCrLf
Catch e As Exception
outputBlock.Text += String.Format("'{0}' and {1} throw a {2}", value, style.ToString, e.GetType.Name) & vbCrLf
End Try
End Sub
End Module
' The example displays the following information:
' ' 123' and None throw a FormatException
' SByte.Parse(" 123", Integer)) = 123
' SByte.Parse("3A", AllowHexSpecifier)) = 58
' SByte.Parse("21", Integer)) = 21
' SByte.Parse("21", AllowHexSpecifier)) = 33
' SByte.Parse("-22", Integer)) = -22
' '-22' and AllowParentheses throw a FormatException
' SByte.Parse("(45)", AllowParentheses)) = -45
' '000,000,056' and Integer throw a FormatException
' SByte.Parse("000,000,056", Integer, AllowThousands)) = 56
using System;
using System.Globalization;
public class Example
{
NumberFormatInfo provider = NumberFormatInfo.CurrentInfo;
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
string stringValue;
NumberStyles style;
stringValue = " 123 ";
style = NumberStyles.None;
CallParseOperation(outputBlock, stringValue, style);
stringValue = "000,000,123";
style = NumberStyles.Integer | NumberStyles.AllowThousands;
CallParseOperation(outputBlock, stringValue, style);
stringValue = "-100";
style = NumberStyles.AllowLeadingSign;
CallParseOperation(outputBlock, stringValue, style);
stringValue = "100-";
style = NumberStyles.AllowLeadingSign;
CallParseOperation(outputBlock, stringValue, style);
stringValue = "100-";
style = NumberStyles.AllowTrailingSign;
CallParseOperation(outputBlock, stringValue, style);
stringValue = "$100";
style = NumberStyles.AllowCurrencySymbol;
CallParseOperation(outputBlock, stringValue, style);
style = NumberStyles.Integer;
CallParseOperation(outputBlock, stringValue, style);
style = NumberStyles.AllowDecimalPoint;
CallParseOperation(outputBlock, "100.0", style);
stringValue = "1e02";
style = NumberStyles.AllowExponent;
CallParseOperation(outputBlock, stringValue, style);
stringValue = "(100)";
style = NumberStyles.AllowParentheses;
CallParseOperation(outputBlock, stringValue, style);
}
private static void CallParseOperation(System.Windows.Controls.TextBlock outputBlock, string stringValue,
NumberStyles style)
{
sbyte number;
try
{
number = sbyte.Parse(stringValue, style);
outputBlock.Text += String.Format("SByte.Parse('{0}', {1})) = {2}",
stringValue, style.ToString(), number) + "\n";
}
catch (Exception e)
{
outputBlock.Text += String.Format("'{0}' and {1} throw a {2}",
stringValue, style.ToString(), e.GetType().Name) + "\n";
}
}
}
// The example displays the following information:
// ' 123 ' and None throw a FormatException
// SByte.Parse('000,000,123', Integer, AllowThousands)) = 123
// SByte.Parse('-100', AllowLeadingSign)) = -100
// '100-' and AllowLeadingSign throw a FormatException
// SByte.Parse('100-', AllowTrailingSign)) = -100
// SByte.Parse('$100', AllowCurrencySymbol)) = 100
// '$100' and Integer throw a FormatException
// SByte.Parse('100.0', AllowDecimalPoint)) = 100
// SByte.Parse('1e02', AllowExponent)) = 100
// SByte.Parse('(100)', AllowParentheses)) = -100
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
See Also