Convert.ToChar Method (String, IFormatProvider)

 

Converts the first character of a specified string to a Unicode character, using specified culture-specific formatting information.

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

Public Shared Function ToChar (
	value As String,
	provider As IFormatProvider
) As Char

Parameters

value
Type: System.String

A string of length 1 or null.

provider
Type: System.IFormatProvider

An object that supplies culture-specific formatting information. This parameter is ignored.

Return Value

Type: System.Char

A Unicode character that is equivalent to the first and only character in value.

Exception Condition
ArgumentNullException

value is null.

FormatException

The length of value is not 1.

value must be a string that contains a single character.

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

The following example converts a string representation of a Char value with the ToChar method, using an IFormatProvider object that displays the type of the format provider for which it is called. The example shows that the format provider is not referenced.

Imports System.Globalization

Public Class DummyProvider
    Implements IFormatProvider

    ' Normally, GetFormat returns an object of the requested type
    ' (usually itself) if it is able; otherwise, it returns Nothing. 
    Public Function GetFormat( argType As Type ) As Object _
        Implements IFormatProvider.GetFormat

        ' Here, GetFormat displays the name of argType, after removing 
        ' the namespace information. GetFormat always returns Nothing.
        Dim argStr  As String = argType.ToString( )
        If argStr = "" Then argStr = "Empty"
        argStr = argStr.Substring( argStr.LastIndexOf( "."c ) + 1 )

        Console.Write( "{0,-20}", argStr )
        Return Nothing

    End Function 
End Class

Module ConvertNonNumericProviderDemo

    Sub Main( )

        ' Create an instance of IFormatProvider.
        Dim provider    As New DummyProvider( )
        Dim format      As String   = "{0,-17}{1,-17}{2}"

        ' Convert these values using DummyProvider.
        Dim Int32A      As String   = "-252645135"   
        Dim DoubleA     As String   = "61680.3855"
        Dim DayTimeA    As String   = "2001/9/11 13:45"

        Dim BoolA       As String   = "True"
        Dim StringA     As String   = "Qwerty"
        Dim CharA       As String   = "$"

        Console.WriteLine( "This example of selected " & _
            "Convert.To<Type>( String, IFormatProvider ) " & vbCrLf & _
            "methods generates the following output. The example " & _
            "displays the " & vbCrLf & "provider type if the " & _
            "IFormatProvider is called." )
        Console.WriteLine( vbCrLf & _
            "Note: For the ToBoolean, ToString, and ToChar " & _
            "methods, the " & vbCrLf & "IFormatProvider object " & _
            "is not referenced." )

        ' The format provider is called for the following conversions.
        Console.WriteLine( )
        Console.WriteLine( format, "ToInt32", Int32A, _
            Convert.ToInt32( Int32A, provider ) )
        Console.WriteLine( format, "ToDouble", DoubleA, _
            Convert.ToDouble( DoubleA, provider ) )
        Console.WriteLine( format, "ToDateTime", DayTimeA, _
            Convert.ToDateTime( DayTimeA, provider ) )

        ' The format provider is not called for these conversions.
        Console.WriteLine( )
        Console.WriteLine( format, "ToBoolean", BoolA, _
            Convert.ToBoolean( BoolA, provider ) )
        Console.WriteLine( format, "ToString", StringA, _
            Convert.ToString( StringA, provider ) )
        Console.WriteLine( format, "ToChar", CharA, _
            Convert.ToChar( CharA, provider ) )

    End Sub
End Module

' This example of selected Convert.To<Type>( String, IFormatProvider )
' methods generates the following output. The example displays the
' provider type if the IFormatProvider is called.
'
' Note: For the ToBoolean, ToString, and ToChar methods, the
' IFormatProvider object is not referenced.
' 
' NumberFormatInfo    ToInt32          -252645135       -252645135
' NumberFormatInfo    ToDouble         61680.3855       61680.3855
' DateTimeFormatInfo  ToDateTime       2001/9/11 13:45  9/11/2001 1:45:00 PM
' 
' ToBoolean        True             True
' ToString         Qwerty           Qwerty
' ToChar           $                $

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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