Convert.ToUInt64 (String, IFormatProvider) converts string to 64-bit unsigned integer using culture-specific format
Imports System.Globalization Module Example Public Sub Main() Dim provider As New NumberFormatInfo() provider.PositiveSign = "pos " provider.NegativeSign = "neg " Dim values() As String = { "1234567891", "+12345678912","pos 12345678912", "12345678912.","neg 1", "-1" } For Each value As String In values Console.Write("{0,-20} --> ", value) Try Console.WriteLine("{0,20}", Convert.ToUInt64(value, provider)) Catch e As FormatException Console.WriteLine("{0,20}", "Invalid Format") Catch e As OverflowException Console.WriteLine("{0,20}", "Numeric Overflow") End Try Next End Sub End Module