Convert.ToByte Method (String)


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Converts the specified string representation of a number to an equivalent 8-bit unsigned integer.

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

Public Shared Function ToByte (
	value As String
) As Byte


Type: System.String

A string that contains the number to convert.

Return Value

Type: System.Byte

An 8-bit unsigned integer that is equivalent to value, or zero if value is null.

Exception Condition

value does not consist of an optional sign followed by a sequence of digits (0 through 9).


value represents a number that is less than Byte.MinValue or greater than Byte.MaxValue.

Using the ToByte(String) method is equivalent to passing value to the Byte.Parse(String) method. value is interpreted by using the formatting conventions of the current thread culture.

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

The following example defines a string array and attempts to convert each string to a Byte. Note that while a null string parses to zero, String.Empty throws a FormatException. Also note that while leading and trailing spaces parse successfully, formatting symbols, such as currency symbols, group separators, or decimal separators, do not.

Module Example
   Public Sub Main()
      Dim values() As String = { Nothing, "", "0xC9", "C9", "101", 
                                 "16.3", "$12", "$12.01", "-4", 
                                 "1,032", "255", "   16  " }
      For Each value In values
            Dim number As Byte = Convert.ToByte(value)
            Console.WriteLine("'{0}' --> {1}", 
                              If(value Is Nothing, "<null>", value), number)
         Catch e As FormatException
            Console.WriteLine("Bad Format: '{0}'", 
                              If(value Is Nothing, "<null>", value))
         Catch e As OverflowException
            Console.WriteLine("OverflowException: '{0}'", value)
         End Try
   End Sub
End Module
' The example displays the following output:
'     '<null>' --> 0
'     Bad Format: ''
'     Bad Format: '0xC9'
'     Bad Format: 'C9'
'     '101' --> 101
'     Bad Format: '16.3'
'     Bad Format: '$12'
'     Bad Format: '$12.01'
'     OverflowException: '-4'
'     Bad Format: '1,032'
'     '255' --> 255
'     '   16  ' --> 16

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