จะทำการ Insert ข้อมูลลงดาต้าเบสครับ ขึ้น ERROR : ExecuteNonQuery requires an open and available Connection. The connection's current state is closed.

Dim Sqlstring As String = ""
Sqlstring += "Insert Into [Transport] ([UserMailTransport], [SiteStartTransport], [SiteEndTransport], [DateTransport], [DateSendTransport], [StatusTransport]) values "
Sqlstring += "('" & labNameUser.Text & "', '" & cbbSiteStart.Text & "', '" & cbbSiteEnd.Text & "', '" & CDate(Date.Today) & "', '" & CDate(dtpDatePost.Text) & "', '1')"

Dim DC As New SqlConnection(frmModule1.conStringAccountAsset)
DC.Open()
Dim DM As New SqlCommand(Sqlstring, DC)
DM.ExecuteNonQuery()

            Dim Sql1 As String = "Select * From Transport where StatusTransport='1' order by IdTransport desc"
            Dim Connect1 As New SqlConnection(frmModule1.conStringAccountAsset)
            Dim DA1 As New SqlDataAdapter(Sql1, Connect1)
            Dim DT1 As New DataTable
            DA1.Fill(DT1)