UInt16.Parse Method (String, NumberStyles, IFormatProvider)
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Updated: August 2009
Converts the string representation of a number in a specified style and culture-specific format to its 16-bit unsigned integer equivalent.
This API is not CLS-compliant. The CLS-compliant alternative is Parse(String).
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 UShort
[CLSCompliantAttribute(false)]
public static ushort Parse(
string s,
NumberStyles style,
IFormatProvider provider
)
Parameters
- s
Type: System.String
A string that represents the number to convert. The string is interpreted by using the style specified by the style parameter.
- style
Type: System.Globalization.NumberStyles
A bitwise combination of enumeration values that indicate 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.
Return Value
Type: System.UInt16
A 16-bit unsigned integer equivalent to the number specified in s.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | s is nulla null reference (Nothing in Visual Basic). |
| ArgumentException | style is not a NumberStyles value. -or- style is not a combination of NumberStyles.AllowHexSpecifier and NumberStyles.HexNumber values. |
| FormatException | s is not in a format compliant with style. |
| OverflowException | s represents a number less than UInt16.MinValue or greater than UInt16.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]
Elements in square brackets ([ and ]) are optional. If style includes NumberStyles.AllowHexSpecifier, the s parameter may include the following elements:
[ws]hexdigits[ws]
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 CurrencyPositivePattern property of the NumberFormatInfo object that is 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. (The method throws an OverflowException if s includes a negative sign and represents a non-zero number.) 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 sign before digits. |
|
A sign after digits. |
|
Parentheses before and after digits to indicate a negative value. |
|
The group separator (,) element. |
|
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. |
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 uses the Parse(String, NumberStyles, IFormatProvider) method to convert various string representations of numbers to 16-bit unsigned integer values.
Imports System.Globalization
Module Example
Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
Dim cultureNames() As String = {"en-US", "fr-FR"}
Dim styles() As NumberStyles = {NumberStyles.Integer, _
NumberStyles.Integer Or NumberStyles.AllowDecimalPoint}
Dim values() As String = {"1702", "+1702.0", "+1702,0", "-1032.00", _
"-1032,00", "1045.1", "1045,1"}
' Parse strings using each culture
For Each cultureName As String In cultureNames
Dim ci As New CultureInfo(cultureName)
outputBlock.Text += String.Format("Parsing strings using the {0} culture", ci.DisplayName) & vbCrLf
' Use each style.
For Each style As NumberStyles In styles
outputBlock.Text += String.Format(" Style: {0}", style.ToString()) & vbCrLf
' Parse each numeric string.
For Each value As String In values
Try
outputBlock.Text += String.Format(" Converted '{0}' to {1}.", value, _
UInt16.Parse(value, style, ci)) & vbCrLf
Catch e As FormatException
outputBlock.Text += String.Format(" Unable to parse '{0}'.", value) & vbCrLf
Catch e As OverflowException
outputBlock.Text += String.Format(" '{0}' is out of range of the UInt16 type.", _
value) & vbCrLf
End Try
Next
Next
Next
End Sub
End Module
' The example displays the following output:
' Parsing strings using the English (United States) culture
' Style: Integer
' Converted '1702' to 1702.
' Unable to parse '+1702.0'.
' Unable to parse '+1702,0'.
' Unable to parse '-1032.00'.
' Unable to parse '-1032,00'.
' Unable to parse '1045.1'.
' Unable to parse '1045,1'.
' Style: Integer, AllowDecimalPoint
' Converted '1702' to 1702.
' Converted '+1702.0' to 1702.
' Unable to parse '+1702,0'.
' '-1032.00' is out of range of the UInt16 type.
' Unable to parse '-1032,00'.
' '1045.1' is out of range of the UInt16 type.
' Unable to parse '1045,1'.
' Parsing strings using the French (France) culture
' Style: Integer
' Converted '1702' to 1702.
' Unable to parse '+1702.0'.
' Unable to parse '+1702,0'.
' Unable to parse '-1032.00'.
' Unable to parse '-1032,00'.
' Unable to parse '1045.1'.
' Unable to parse '1045,1'.
' Style: Integer, AllowDecimalPoint
' Converted '1702' to 1702.
' Unable to parse '+1702.0'.
' Converted '+1702,0' to 1702.
' Unable to parse '-1032.00'.
' '-1032,00' is out of range of the UInt16 type.
' Unable to parse '1045.1'.
' '1045,1' is out of range of the UInt16 type.
using System;
using System.Globalization;
public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
string[] cultureNames = { "en-US", "fr-FR" };
NumberStyles[] styles = { NumberStyles.Integer,
NumberStyles.Integer | NumberStyles.AllowDecimalPoint };
string[] values = { "1702", "+1702.0", "+1702,0", "-1032.00",
"-1032,00", "1045.1", "1045,1" };
// Parse strings using each culture
foreach (string cultureName in cultureNames)
{
CultureInfo ci = new CultureInfo(cultureName);
outputBlock.Text += String.Format("Parsing strings using the {0} culture",
ci.DisplayName) + "\n";
// Use each style.
foreach (NumberStyles style in styles)
{
outputBlock.Text += String.Format(" Style: {0}", style.ToString()) + "\n";
// Parse each numeric string.
foreach (string value in values)
{
try
{
outputBlock.Text += String.Format(" Converted '{0}' to {1}.", value,
UInt16.Parse(value, style, ci)) + "\n";
}
catch (FormatException)
{
outputBlock.Text += String.Format(" Unable to parse '{0}'.", value) + "\n";
}
catch (OverflowException)
{
outputBlock.Text += String.Format(" '{0}' is out of range of the UInt16 type.",
value) + "\n";
}
}
}
}
}
}
// The example displays the following output:
// Parsing strings using the English (United States) culture
// Style: Integer
// Converted '1702' to 1702.
// Unable to parse '+1702.0'.
// Unable to parse '+1702,0'.
// Unable to parse '-1032.00'.
// Unable to parse '-1032,00'.
// Unable to parse '1045.1'.
// Unable to parse '1045,1'.
// Style: Integer, AllowDecimalPoint
// Converted '1702' to 1702.
// Converted '+1702.0' to 1702.
// Unable to parse '+1702,0'.
// '-1032.00' is out of range of the UInt16 type.
// Unable to parse '-1032,00'.
// '1045.1' is out of range of the UInt16 type.
// Unable to parse '1045,1'.
// Parsing strings using the French (France) culture
// Style: Integer
// Converted '1702' to 1702.
// Unable to parse '+1702.0'.
// Unable to parse '+1702,0'.
// Unable to parse '-1032.00'.
// Unable to parse '-1032,00'.
// Unable to parse '1045.1'.
// Unable to parse '1045,1'.
// Style: Integer, AllowDecimalPoint
// Converted '1702' to 1702.
// Unable to parse '+1702.0'.
// Converted '+1702,0' to 1702.
// Unable to parse '-1032.00'.
// '-1032,00' is out of range of the UInt16 type.
// Unable to parse '1045.1'.
// '1045,1' is out of range of the UInt16 type.
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
Reference
Other Resources
Change History
Date |
History |
Reason |
|---|---|---|
August 2009 |
Revised extensively. |
Information enhancement. |