vb.net oracle database datagridview1.datasource=rs is not working

Imports System.Data.Odbc Imports System.Data.OleDb Imports ADODB Public Class Form3

Dim str As String

Dim conn As ADODB.Connection
Dim rs As ADODB.Recordset
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    conn = New ADODB.Connection
    rs = New ADODB.Recordset
    str = "Select * from studenttable where(dept='" & ComboBox1.SelectedItem & "' and year='" & ComboBox2.SelectedItem & "')"

    conn.Open("driver={microsoft ODBC for Oracle};uid=hr;pwd=hr;")

    rs.Open(str, conn, ADODB.CursorTypeEnum.adOpenDynamic, ADODB.LockTypeEnum.adLockPessimistic)

    TextBox1.Text = rs.Fields.Count

    MsgBox("en1")

    Me.DataGridView1.DataSource = rs



    rs.Close()
    MsgBox("en2")
End Sub

Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    conn = New ADODB.Connection

    If (conn.State = ConnectionState.Open) Then

        conn.Close()

    End If

End Sub

End Class

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