ASP.NET(VB) มีปัญหาเกี่ยวกับการ วนลูป select ข้อมูล นะคับ ช่วยดูให้หน่อยคับ ทำไมมันทำแค่รอบเดี่ยว..

Imports System.Data
Imports System.Data.OracleClient
Partial Class Sum_salary_grupt
    Inherits System.Web.UI.Page
    Dim Conn As OracleConnection
    Dim Cmd As OracleCommand
    Dim Cmd2 As OracleCommand
    Dim Cmd3 As OracleCommand
    Dim sqlx As String
    Dim dtReader As OracleDataReader
    Dim dtReader2 As OracleDataReader
    Dim dtReader3 As OracleDataReader
    
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim strconnstring As String
        strconnstring = "Data Source=pkmreg;User Id=pkmreg;Password=oracle;"
        Conn = New OracleConnection(strconnstring)
        Conn.Open()
    End Sub

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        select_per()
    End Sub

    Sub select_per()
        If ComboBox1.Text <> "" And DropDownList2.Text <> "" Then

            sqlx = "SELECT OFFICERCODE FROM PEROFFICER WHERE FACULTYID = '" & Me.ComboBox1.Text & "'"
            Cmd = New OracleCommand(sqlx, Conn)
            dtReader = Cmd.ExecuteReader()
            While dtReader.Read()
                Dim sum_in As Single
                Dim sum_ina As Single
                Dim sumz As Single
                Dim sum_ex As Single
                Dim all_sum_pay As Single
                Dim code As String = dtReader.Item("OFFICERCODE")

                '############ รายหัก ############################################
                Dim sqlx_cou2 As String = "SELECT COUNT(REX_ID) AS COU_EX FROM PER_SALARY_ROUTINE_EX WHERE OFFICERCODE = '" & code & "' AND REX_IOD_CODE = '" & Me.DropDownList2.Text & "'"
                Cmd = New OracleCommand(sqlx_cou2, Conn)
                dtReader = Cmd.ExecuteReader
                dtReader.Read()
                Dim cou_ex As String = dtReader.Item("COU_EX")
                If cou_ex <> "0" Then
                    Dim sqlx_ex As String = "SELECT SUM(REX_NUM) AS REX_SUM FROM PER_SALARY_ROUTINE_EX WHERE OFFICERCODE = '" & code & "' AND REX_IOD_CODE = '" & Me.DropDownList2.Text & "'"
                    Cmd3 = New OracleCommand(sqlx_ex, Conn)
                    dtReader3 = Cmd3.ExecuteReader
                    dtReader3.Read()
                    sum_ex = dtReader3.Item("REX_SUM")
                    MsgBox("pay : " & sum_ex & "code : " & code)
                End If
                ''############ รายได้ ############################################
                Try
                    Dim sqlx_cou1 As String = "SELECT COUNT(RIN_ID) AS COU_IN FROM PER_SALARY_ROUTINE_IN WHERE OFFICERCODE = '" & code & "'"
                    Cmd = New OracleCommand(sqlx_cou1, Conn)
                    dtReader = Cmd.ExecuteReader
                    dtReader.Read()
                    Dim cou_in As String = dtReader.Item("COU_IN")
                    If cou_in <> "0" Then
                        Dim sqlx_in As String = "SELECT SUM(RIN_NUM) AS RIN_SUM FROM PER_SALARY_ROUTINE_IN WHERE OFFICERCODE = '" & code & "'"
                        Cmd2 = New OracleCommand(sqlx_in, Conn)
                        dtReader2 = Cmd2.ExecuteReader
                        dtReader2.Read()
                        sum_in = dtReader2.Item("RIN_SUM")
                    End If
                    '------------------------------------------------------------------------
                    Dim sqlx_cou3 As String = "SELECT COUNT(AD_ID) AS COU_INA FROM PER_SALARY_ROUTINE_ADD WHERE OFFICERCODE = '" & code & "' AND AD_IOD_CODE = '" & Me.DropDownList2.Text & "'"
                    Cmd = New OracleCommand(sqlx_cou3, Conn)
                    dtReader = Cmd.ExecuteReader
                    dtReader.Read()
                    Dim cou_inx As String = dtReader.Item("COU_INA")
                    If cou_inx <> "0" Then
                        Dim sqlx_in As String = "SELECT SUM(AD_NUM) AS ADD_SUM FROM PER_SALARY_ROUTINE_ADD WHERE OFFICERCODE = '" & code & "' AND AD_IOD_CODE = '" & Me.DropDownList2.Text & "'"
                        Cmd2 = New OracleCommand(sqlx_in, Conn)
                        dtReader2 = Cmd2.ExecuteReader
                        dtReader2.Read()
                        sum_ina = dtReader2.Item("ADD_SUM")
                    End If
                    '############ ทำงานเดือน ######################################
                    If sum_in <> "0" And sum_ina <> "0" Then
                        sumz = sum_in + sum_ina
                        Dim muney_pay1 As Single = sumz - sum_ex
                        all_sum_pay = muney_pay1 'จ่ายจริง
                    ElseIf sum_ina = "0" Then
                        Dim muney_pay2 As Single = sum_in - sum_ex
                        all_sum_pay = muney_pay2 'จ่ายจริง
                    End If

                Catch ex As Exception

                End Try
            End While
        End If
    End Sub
End Class