Error: HttpWebRequest on TextChanged Event [solved]

Imports System.Net
Imports System
Imports System.Text
Imports System.IO
Public Class Form1




    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        F1 = Me
    End Sub

    Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
        If TextBox1.Text = " " Then
            DialogResult = Windows.Forms.DialogResult.OK
        Else
            Dim request As System.Net.HttpWebRequest = System.Net.HttpWebRequest.Create(TextBox1.Text)
            Dim response As HttpWebResponse = request.GetResponse
            Dim sr As System.IO.StreamReader = New System.IO.StreamReader(response.GetResponseStream)
            Dim code As String = sr.ReadToEnd
            RichTextBox1.Text = code


        End If
    End Sub

    Private Sub Button10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button10.Click
        TextBox1.Clear()
    End Sub
End Class