在vb中读取xml base64内容

Question

我尝试将x64内容从base64解码为string 这是我的代码
inr1是xmlReader

Dim inv As String = inr1.ReadElementContentAsString()

'inv值有值[aGVsbG8 =] whic是你好

Dim binv() As Byte = Encoding.UTF8.GetBytes(inv)

'binv有值好

Dim n3 As String = inr1.ReadElementContentAsBase64(binv, 0, binv.Length).ToString

但是n3是Nothing :(？