Exporting Data From Sql Server To Excel From Sql Server Using Asp.net

Hi,
I am new to ASP.net. I have worked on a VB.net code to export data from sql server to excel. The code is simple and works well. Now I am placing this code in a button click event in a asp.net web project. The code has bugs now and I am not sure how to solve those. Any help is appreciated. Thanks.

CODE:
Protected Sub btnDumpMaterial_Click(ByVal sender As Object, ByVal e As System.EventArgs)
'ErrorMsg.Show("Not Implemented Yet1")
'lblName.Text = txtLast.Text & ", " & txtFirst.Text
Dim DBConnection As String = "Provider=SQLOLEDB.1;uid=sa;password=test ;database=Northwind;DataSource={localhost}"

Dim sql As String = "SELECT CustomerId, CompanyName, ContactName From Customers"
Dim Conn As New ADODB.Connection
Dim rs As New ADODB.Recordset


Dim oExcel As Excel.Application
Dim oBook As Excel.Workbook
Dim oSheet As Excel.Worksheet


oExcel = CreateObject("Excel.Application")
oExcel.Visible = True

oBook = oExcel.Workbooks.Add
oSheet = oBook.ActiveSheet


Conn.Open(DBConnection, "sa", "test", -1)
rs.Open(sql, DBConnection, ADODB.CursorTypeEnum.adOpenStatic, ADODB.LockTypeEnum.adLockBatchOptimistic, 1)



oSheet.Range("A1").CopyFromRecordset(rs)
rs.Close()
Conn.Close()
End Sub
ERROR MESSAGE:

Type 'ADODB.Connection' is not defined
Type 'ADODB.Recordset' is not defined
Type 'Excel.Application' is not defined
Type 'Excel.Worksheet' is not defined
Name 'ADODB' not declared