VB.NET按字节截取字符串

代码实现从字符串左端开始按字节截取字符串（从右端或指定位置开始按字节截取的代码可以参考以下代码自行修改）

Private Function SubChar(ByVal s As String, ByVal CharCount As Integer) As String
        Dim strRtn As String
        Dim bytArray() As Byte
        Dim chrArray() As Char
        Dim intI As Integer
        bytArray = System.Text.Encoding.Default.GetBytes(s)
        If CharCount > System.Text.Encoding.Default.GetCharCount(bytArray) Then
            strRtn = s
        Else
            chrArray = System.Text.Encoding.Default.GetChars(bytArray, 0, CharCount)
            For intI = 0 To chrArray.Length - 1
                strRtn = strRtn & chrArray(intI)
            Next
        End If
        Return strRtn
End Function