问将字符串编码为vb.net -8

EN

Public Shared Function encode(ByVal str As String) As String
    'supply True as the construction parameter to indicate
    'that you wanted the class to emit BOM (Byte Order Mark)
    'NOTE: this BOM value is the indicator of a UTF-8 string
    Dim utf8Encoding As New System.Text.UTF8Encoding(True)
    Dim encodedString() As Byte

    encodedString = utf8Encoding.GetBytes(str)

    Return utf8Encoding.GetString(encodedString)
End Function

Public Class Form1


    Private Sub BtnClearText_Click(sender As Object, e As EventArgs) Handles BtnClearText.Click
        TxtEncodedValue.Text = ""
        TxtNormalValue.Text = ""
    End Sub

    Private Sub BtnEncode_Click(sender As Object, e As EventArgs) Handles BtnEncode.Click
        Dim byt As Byte() = System.Text.Encoding.UTF8.GetBytes(TxtNormalValue.Text)
        TxtEncodedValue.Text = Convert.ToBase64String(byt)
    End Sub

    Private Sub BtnDecode_Click(sender As Object, e As EventArgs) Handles BtnDecode.Click
        Dim b As Byte() = Convert.FromBase64String(TxtEncodedValue.Text)
        TxtNormalValue.Text = System.Text.Encoding.UTF8.GetString(b)
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    End Sub

 
End Class