怎么把文本框中的内容从utf8变为ansi

在google中正常，但是用baidu ，我分析好像是textbox1.text的编码是utf8的原因，百度结果显示textbox1.text无法正确显示是乱码

 Dim myWebClient As New WebClient()

        Dim sQuery As String

        sQuery = "http://mp3.baidu.com/m"

        Dim myQueryStringCollection As New NameValueCollection()

        myQueryStringCollection.Add("word", TextBox1.Text)

        myQueryStringCollection.Add("rn", "")

        myQueryStringCollection.Add("f", "ms")

        myQueryStringCollection.Add("tn", "baidump3")

        myQueryStringCollection.Add("lm", "0")

        myQueryStringCollection.Add("ct", "134217728")

        myQueryStringCollection.Add("submit", "百度搜索")

        myWebClient.QueryString = myQueryStringCollection

        Dim strm As Stream = myWebClient.OpenRead(sQuery)

        Dim sr As New StreamReader(strm, System.Text.Encoding.Default)

        Dim sLine As String

        RichTextBox1.Clear()

 

        Do

            sLine = sr.ReadLine

            sLine = HttpUtility.HtmlDecode(sLine)

            RichTextBox1.Text += sLine + vbCrLf

        Loop Until sr.EndOfStream