ถามผู้รู้คับ ผมเพิ่งเริ่มหัดเขียน vb แล้วมันติดเหมือนerrorอะครับ แต่ฐานข้อมูลผมไม่ผิดนะครับ

Public Class Form1
    Friend cn As New SqlConnection("Data sources=.\SQLExpress; Initial Catalog=stocktest;Integrated Security=sspi;")
    Friend cmd As New SqlCommand
    Friend DA As New SqlDataAdapter
    Friend DS As New DataSet
    Friend sql As String

    Public Sub open_database()
        If cn.State = ConnectionState.Closed Then cn.Open()

    End Sub

    Private Sub DataGridView1_CellContentClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick

    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        open_database()
        sql = "select * from product"
        DA = New SqlDataAdapter(sql, cn)
        DS = New DataSet
        DA.Fill(DS, "table")
        DataGridView1.DataSource = DS.Tables("table")


    End Sub
End Class