vb.net การรู้เกี่ยวกับ การค้นหาข้อมูล แบบ การ join 2 ตาราง ช่วยทีครับ

Private Sub cmdSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSearch.Click
        Dim qry = From p In db.Resume2s Join c In db.Day_date2s On p.ID Equals c.ID _
        Select C1 = c.ID_Date, P1 = p.ID, P2 = p.Title, P3 = p.Name, P4 = p.LastName, _
               C2 = c.Name, C3 = c.Day_date, C4 = c.Time


        Select Case cboSearch.SelectedIndex
                Case 0
                    qry = (From c In db.Day_date2s) _
                    .Where(Function(s) s.ID_Date.StartsWith(txtSearch.Text))
                Case 1
                    qry = (From c In db.Day_date2s) _
                  .Where(Function(s) s.ID.StartsWith(txtSearch.Text))
                Case 2
                    qry = (From p In db.Resume2s) _
                  .Where(Function(s) s.Name.StartsWith(txtSearch.Text))
                Case 3
                    qry = (From c In db.Day_date2s) _
                 .Where(Function(s) s.Name.StartsWith(cboDoctor.SelectedValue))
                Case 4
                    qry = (From c In db.Day_date2s) _
                 .Where(Function(s) s.Time.StartsWith(cboTime.SelectedValue))
            End Select
            dgvDateTime.DataSource = qry
    End Sub