ASCII to Hex

[MS-47]

I'm currently using the following code, but it won't convert "advanced ASCII", such as: ™ ¥ © etc...
It just gives them a question mark value (3F).

How can I make it convert them correctly?

        Dim str As String = TextBox1.Text
        Dim bytes() As Byte
        Dim hexn As System.Text.StringBuilder = New System.Text.StringBuilder
        bytes = System.Text.ASCIIEncoding.ASCII.GetBytes(str)
        For i As Integer = 0 To bytes.Length - 1
            hexn.Append(bytes(i).ToString("x"))
        Next
        TextBox2.AppendText((hexn.ToString()))

[formlesstree4]

I'm currently using the following code, but it won't convert "advanced ASCII", such as: ™ ¥ © etc...
It just gives them a question mark value (3F).

How can I make it convert them correctly?

        Dim str As String = TextBox1.Text
        Dim bytes() As Byte
        Dim hexn As System.Text.StringBuilder = New System.Text.StringBuilder
        bytes = System.Text.ASCIIEncoding.ASCII.GetBytes(str)
        For i As Integer = 0 To bytes.Length - 1
            hexn.Append(bytes(i).ToString("x"))
        Next
        TextBox2.AppendText((hexn.ToString()))

...because they're not ASCII; change encoding to UTF-8 instead or Unicode.