ToSingle Method (String, IFormatProvider)

Convert.ToSingle Method (String, IFormatProvider)

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Converts the specified String representation of a number to an equivalent single-precision floating point number using the specified culture-specific formatting information.

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

'Declaration
Public Shared Function ToSingle ( _
	value As String, _
	provider As IFormatProvider _
) As Single

Parameters

value
Type: System.String
A String containing a number to convert.
provider
Type: System.IFormatProvider
An IFormatProvider interface implementation that supplies culture-specific formatting information.

Return Value

Type: System.Single
A single-precision floating point number equivalent to the value of value.
-or-
Zero if value is Nothing.

ExceptionCondition
FormatException

value is not a number in a valid format.

OverflowException

value represents a number less than MinValue or greater than MaxValue.

The return value is the result of invoking the Single.Parse method on value.

provider is an IFormatProvider instance that obtains a NumberFormatInfo object. The NumberFormatInfo object provides culture-specific information about the format of value. If provider is Nothing, the NumberFormatInfo for the current culture is used.

If you prefer not to handle an exception if the conversion fails, you can call the Single.TryParse method instead. It returns a Boolean value that indicates whether the conversion succeeded or failed.

The following code example converts String representations of Single values with the ToSingle method, using an IFormatProvider object.


' Example of the Convert.ToSingle( String ) and 
' Convert.ToSingle( String, IFormatProvider ) methods.
Imports System.Globalization

Module Example

   Dim formatter As String = "{0,-22}{1,-20}{2}"

   ' Get the exception type name; remove the namespace prefix.
   Function GetExceptionType(ByVal ex As Exception) As String

      Dim exceptionType As String = ex.GetType().ToString()
      GetExceptionType = exceptionType.Substring( _
          exceptionType.LastIndexOf("."c) + 1)
   End Function

   Sub ConvertToSingle(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal numericStr As String, _
       ByVal provider As IFormatProvider)

      Dim defaultValue As Object
      Dim providerValue As Object

      ' Convert numericStr to Single without a format provider.
      Try
         defaultValue = Convert.ToSingle(numericStr)
      Catch ex As Exception
         defaultValue = GetExceptionType(ex)
      End Try

      ' Convert numericStr to Single with a format provider.
      Try
         providerValue = Convert.ToSingle(numericStr, provider)
      Catch ex As Exception
         providerValue = GetExceptionType(ex)
      End Try

      outputBlock.Text &= String.Format(formatter, numericStr, _
          defaultValue, providerValue) & vbCrLf
   End Sub

   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' Create a NumberFormatInfo object and set several of its
      ' properties that apply to numbers.
      Dim provider As NumberFormatInfo = New NumberFormatInfo()

      provider.NumberDecimalSeparator = ","
      provider.NumberGroupSeparator = "."
      provider.NumberGroupSizes = New Integer() {3}

      outputBlock.Text &= String.Format("This example of" & vbCrLf & _
          "  Convert.ToSingle( String ) and " & vbCrLf & _
          "  Convert.ToSingle( String, IFormatProvider ) " & _
          vbCrLf & "generates the " & _
          "following output when run in the [{0}] culture.", _
          CultureInfo.CurrentCulture.Name) & vbCrLf
      outputBlock.Text &= String.Format(vbCrLf & _
          "Several strings are converted to Single values, " & _
          "using " & vbCrLf & "default formatting " & _
          "and a NumberFormatInfo object." & vbCrLf) & vbCrLf
      outputBlock.Text &= String.Format(formatter, "String to convert", _
          "Default/exception", "Provider/exception") & vbCrLf
      outputBlock.Text &= String.Format(formatter, "-----------------", _
          "-----------------", "------------------") & vbCrLf

      ' Convert strings, with and without an IFormatProvider.
      ConvertToSingle(outputBlock, "1234567", provider)
      ConvertToSingle(outputBlock, "1234.567", provider)
      ConvertToSingle(outputBlock, "1234,567", provider)
      ConvertToSingle(outputBlock, "12,345.67", provider)
      ConvertToSingle(outputBlock, "12.345,67", provider)
      ConvertToSingle(outputBlock, "1,234,567.89", provider)
      ConvertToSingle(outputBlock, "1.234.567,89", provider)
   End Sub
End Module

' This example of
'   Convert.ToSingle( String ) and
'   Convert.ToSingle( String, IFormatProvider )
' generates the following output when run in the [en-US] culture.
' 
' Several strings are converted to Single values, using
' default formatting and a NumberFormatInfo object.
' 
' String to convert     Default/exception   Provider/exception
' -----------------     -----------------   ------------------
' 1234567               1234567             1234567
' 1234.567              1234.567            1234567
' 1234,567              1234567             1234.567
' 12,345.67             12345.67            FormatException
' 12.345,67             FormatException     12345.67
' 1,234,567.89          1234568             FormatException
' 1.234.567,89          FormatException     1234568


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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