半角数字验证 Encoding

 Imports System.Text.RegularExpressions

  

''' <summary>
    ''' Shift-JISエンコーディング
    ''' </summary>
    ''' <remarks></remarks>
    Public Shared ReadOnly DefaultEncoding As Encoding = Encoding.GetEncoding(932)

    ''' <summary>
    ''' 文字列の桁数（Shift-JISでのバイト数）を取得する。
    ''' </summary>
    ''' <param name="s">入力された文字列。</param>
    ''' <returns>文字列の桁数</returns>
    ''' <remarks></remarks>
    Public Shared Function GetLength(ByVal s As String) As Integer
        If Not IsInput(s) Then
            Return 0
        End If

        Return  DefaultEncoding.GetByteCount(s)
    End Function

   ''' <summary>
    ''' 配列の各項目の半角数字固定桁数チェック
    ''' </summary>
    ''' <param name="strs"></param>
    ''' <param name="length">長さ</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function CheckArrayIsNum(ByVal strs As String(), ByVal length As Integer) As Boolean

        For Each str As String In strs
            If GetLength(str) <> length Or Regex.IsMatch(str, "[^0-9]") Then
                Return False
            End If
        Next
        Return True

    End Function

 

https://msdn.microsoft.com/zh-cn/library/system.text.encoding(VS.80).aspx