Convert.ToByte(String,IFormatProvider) converts string to 8-bit unsigned integer, using culture-specific format
Imports System.Globalization Module Example Public Sub Main() Dim provider As New NumberFormatInfo() With provider .PositiveSign = "pos " .NegativeSign = "neg " .NumberDecimalSeparator = "." End With Dim numericStrings() As String = { "234", "+234", "pos 234", "234.", _ "255", "256", "-1" } For Each numericString As String In numericStrings Console.Write("'{0,-8}' -> ", numericString) Try Dim number As Byte = Convert.ToByte(numericString, provider) Console.WriteLine(number) Catch ex As FormatException Console.WriteLine("Incorrect Format") Catch ex As OverflowException Console.WriteLine("Overflows a Byte") End Try Next End Sub End Module