popluate combobox fill gridview from webservice

<WebMethod()> Public Function dat(ByVal services As String) As DataSet
        Dim cn As New SqlConnection
        Dim da As SqlDataAdapter
        Dim strSelect As String
        Dim ds As DataSet
        Dim cnstring As String
        cnstring = "Data Source=.\SQLExpress; Initial Catalog=PUBS; Integrated Security=True;"
 
        cn = New SqlConnection(cnstring)
        cn.Open()
 
        'strSelect = "SELECT DISTINCT stores.stor_name, sales.stor_id FROM (stores INNER JOIN sales ON stores.stor_id = sales.stor_id)"
        strSelect = "SELECT * FROM Stores"
 
        da = New SqlDataAdapter(strSelect, cn)
        ds = New DataSet
        da.Fill(ds, "Stores")
        dat = ds
 
    End Function
 
    <WebMethod()> Public Function data(ByVal selected As String) As DataSet
        Dim cnstring As String
        Dim strSelect As String
        Dim ds As DataSet
        Dim da As SqlDataAdapter
 
        cnstring = "Data Source=.\SQLExpress; Initial Catalog=PUBS; Integrated Security=True;"
 
        strSelect = "SELECT stor_id, ord_num, ord_date, qty, payterms, title_id FROM Sales WHERE stor_id=7067"
 
        Dim cn As New SqlConnection(cnstring)
        cn.Open()
        Dim cmd As New SqlCommand(strSelect, cn)
 
        da = New SqlDataAdapter(strSelect, cn)
        ds = New DataSet
 
        da.Fill(ds, "Sales")
        Return ds
 
    End Function
 
 
 
Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim combo As New localhost.Service()
        ComboBox1.DataSource = combo.dat.Tables(0)
        ComboBox1.DisplayMember = "stor_name"
        ComboBox1.ValueMember = "stor_id"
 
    End Sub
 
    Public Sub ComboBox1_SelectedIndexChanged(ByVal test As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
 
        Dim combo1 As New localhost.Service()
        DataGridView1.DataSource = combo1.data
    End Sub
End Class