INSERT ไม่ผ่านคับรบกวนช่วยดูให้ที นั่งมานานแล้วไม่ออกซักทีคับ ExecuteReader requires an open and available Connection. The connection's current state is closed.

Dim sql As String
        Conn = New OleDbConnection()
        Conn.ConnectionString = strConnString
        Conn.Open()
      
        sql = "INSERT INTO [TB_Rent] (Cus_ID,Em_ID,Rent_Date) Values ('" & txtfind.Text & "','" & txtEmc.Text & "','" & Date.Today & "')"
        Dim cmd As OleDbCommand = New OleDbCommand(sql, Conn)
        Dim rdr As OleDbDataReader = cmd.ExecuteReader()


        Dim sql2 As String
        Conn = New OleDbConnection()
        Conn.ConnectionString = strConnString

        Dim i As Integer
        i = DataGridView1.CurrentRow.Index
        sql2 = "INSERT INTO [TB_RentDetail] (Book_ID,Rent_Price,Rent_Quantity,Rent_Date,Deadline_Date,Price_Penalty,Price_Total,Status) Values ('" & DataGridView1.Item(0, i).Value & "','" & DataGridView1.Item(1, i).Value & "','" & lbCheck.Text & "','" & DataGridView1.Item(3, i).Value & "','" & Date.Today.AddDays(+3) & "','" & DataGridView1.Item(4, i).Value & "','" & lbTotal.Text & "','" & CInt(lbCheck.Text) - CInt(txtRentc.Text) & "')"
        Dim cmd2 As OleDbCommand = New OleDbCommand(sql2, Conn)
        Dim rdr2 As OleDbDataReader = cmd.ExecuteReader()

        Conn.Close()

Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
        If (txtMemberID.Text = "") Then
            MessageBox.Show("กรุณาระบุรหัสบัตรผู้ยืม !!!", "ผลการตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Information)
            txtMemberID.Focus()
            Exit Sub
        End If


        If lsvEquList.Items.Count = 0 Then
            MessageBox.Show("กรุณาป้อนรายการยืมอุปกรณ์ !!!", "ผลการตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Information)
            txtEquID.Focus()
            Exit Sub
        End If

        Dim sqlLend As String = ""
        Dim comLend As SqlCommand = New SqlCommand


        With Conn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strConn
            .Open()
        End With

        Try
            If MessageBox.Show("คุณต้องการบันทึกรายการยืมอุปกรณ์ ใช่หรือไม่?", "คำยืนยัน", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = DialogResult.Yes Then

                AutoGenerateLendID()
                sqlLend = "INSERT INTO Lend (LendID,MemberID,NetReceived,Return_StatusAll) "
                sqlLend &= " VALUES('" & LastLendID & "',"
                sqlLend &= "'" & txtMemberID.Text & "',"
                sqlLend &= "0,'0')"

                With comLend
                    .CommandType = CommandType.Text
                    .CommandText = sqlLend
                    .Connection = Conn
                    .ExecuteNonQuery()
                End With

                Dim i As Integer = 0
                Dim tmpEquipmentID As String = ""

                Dim sqlEquipment As String = ""
                Dim tmpEquipmentInStock As Integer = 0
                Dim tmpEquipmentInLend As Integer = 0

                Dim tmpEquipmentNum As Integer = 0
                Dim tmpDateNum As Integer = 0
                Dim tmpAmount As Integer = 0
                Dim tmpSum As Integer = 0
                Dim tmpNet As Integer = 0

                Dim tmpLendDate As Date
                Dim tmpReturnDate As Date

                tmpLendDate = Date.Now


                For i = 0 To lsvEquList.Items.Count - 1
                    sqlLend = "INSERT INTO LendDetail(LendID,EquipmentID,Lend_Date,"
                    sqlLend &= " Return_Date,Lend_Num,AmountReceived,Return_Status)"
                    sqlLend &= " VALUES('" & LastLendID & "',"

                    tmpEquipmentID = lsvEquList.Items(i).SubItems(0).Text
                    tmpEquipmentNum = CInt(lsvEquList.Items(i).SubItems(2).Text)
                    tmpDateNum = CInt(lsvEquList.Items(i).SubItems(3).Text)
                    tmpAmount = CInt(lsvEquList.Items(i).SubItems(4).Text)

                    sqlLend &= "'" & tmpEquipmentID & "',"
                    sqlLend &= "'" & tmpLendDate & "',"

                    tmpReturnDate = tmpLendDate.AddDays(tmpDateNum)

                    sqlLend &= "'" & tmpReturnDate & "',"
                    sqlLend &= tmpEquipmentNum & ","
                    sqlLend &= tmpNet & ","
                    sqlLend &= "'0')"

                    With comLend
                        .CommandText = sqlLend
                        .ExecuteNonQuery()
                    End With

                    sqlEquipment = "SELECT EquipmentID,Equip_InStock,Equip_InLend FROM Equipment"
                    sqlEquipment &= " WHERE (EquipmentID='" & tmpEquipmentID & "')"

                    da.SelectCommand.CommandText = sqlEquipment
                    da.Fill(ds, "Equipment")

                    tmpEquipmentInStock = CInt(ds.Tables("Equipment").Rows(0).Item("Equip_InStock"))
                    tmpEquipmentInLend = CInt(ds.Tables("Equipment").Rows(0).Item("Equip_InLend"))
                    ds.Tables("Equipment").Clear()

                    sqlLend = "UPDATE Equipment"
                    sqlLend &= " SET Equip_InStock=" & tmpEquipmentInStock - tmpEquipmentNum & ","
                    sqlLend &= " Equip_InLend=" & tmpEquipmentInLend + tmpEquipmentNum
                    sqlLend &= " WHERE (EquipmentID='" & tmpEquipmentID & "')"

                    With comLend
                        .CommandText = sqlLend
                        .ExecuteNonQuery()
                    End With
                Next


                MessageBox.Show("บันทึกรายการยืมอุปกรณ์เรียบร้อยแล้ว !!!", "ผลการทำงาน", MessageBoxButtons.OK, MessageBoxIcon.Information)

                If IsInstallPrinter() = True Then
                    If prDlg.ShowDialog = DialogResult.OK Then
                        prDoc.Print()
                    End If
                Else
                    MessageBox.Show("กรุณาติดตั้งเครื่อง Printer ก่อนสั่งพิมพ์เอกสาร", "ผลการตรวจสอบ", MessageBoxButtons.OK, MessageBoxIcon.Information)
                End If

                ClearAllMemberData()
                ClearAllEquipmentData()
                lsvEquList.Items.Clear()

                cboPosition.SelectedIndex = 0
                txtMemberID.Enabled = True
                txtMemberID.Focus()
            End If
        Catch ErrProcess As Exception
            MessageBox.Show("ไม่สามารถบันทึกรายการยืมอุปกรณ์ได้ เนื่องจาก " & ErrProcess.Message, "ข้อผิดพลาด", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            Exit Sub
        Finally
            Conn.Close()
        End Try
    End Sub