How to read multiple sql reader at VB.NET?

Question

Well,  i have a problem with Read clause in VB.NET.

My Database:

MS_KARYAWAN         MS_KESEHATAN

--------------------        ------------------------

ID_KARYAWAN          ID_KESEHATAN

NAMA_KARYAWAN     ID_KARYAWAN

JABATAN                    PERIODE

PANGKAT                   NILAI_PENGGANTIAN

My code

---------------------------------------------------------------------------

Private Sub cmbPeriode_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmbPeriode.SelectedIndexChanged

        If Not con.State = ConnectionState.Open Then

            con.Open()

        End If

        Dim query As String

        Dim dr As SqlDataReader

        Dim j As Integer

        j = Val(cmbPeriode.SelectedItem)

        For i As Integer = 0 To cmbPeriode.Items.Count Step 1

            If cmbPeriode.SelectedIndex = i Then

                query = String.Format("SELECT TOP (1) NILAI_PENGGANTIAN FROM MS_KESEHATAN WHERE ID_KARYAWAN='" + Mid(cmbID_KARYAWAN.Text, 1, 10) + "' AND PERIODE='" & Me.cmbPeriode.Text & "' ORDER BY NILAI_PENGGANTIAN DESC;")

                cmd.CommandText = query

                If cmd.ExecuteScalar() = "" Then

                    con.Close()

                    If Not con.State = ConnectionState.Open Then

                        con.Open()

                    End If

                    cmd.CommandText = "SELECT MS_KARYAWAN.JABATAN FROM MS_KARYAWAN INNER JOIN MS_KESEHATAN ON MS_KARYAWAN.ID_KARYAWAN = MS_KESEHATAN.ID_KARYAWAN WHERE MS_KESEHATAN.ID_KARYAWAN='" & Mid(cmbID_KARYAWAN.Text, 1, 10) & "' AND MS_KARYAWAN.JABATAN LIKE '%Kepala Divisi%';"

                    dr = cmd.ExecuteReader()

                    If dr.Read = True Then

                        txtNilaiPengganti.Text = "1100000"

                    Else

Msgbox("Error")

                    End If

                Else

                    txtNilaiPengganti.Text = cmd.ExecuteScalar().ToString()

                End If

            End If

        Next

    End Sub

--------------------------------------------------------------------------------------

The bold is the code which has issues

Mid(cmbID_KARYAWAN.Text, 1, 10) ---> is used to get the PK of ID_KARYAWAN on combobox

My algorithm:

When the query on ExecuteScalar running

then do the next query which is only read for related table

if the query value is TRUE then it should be inside the If statement

if it FALSE then do to Else Statement

(in Else statement i will do the same query as the previous one using INNER JOIN, but in different WHERE clause)

If i execute, it always throw to else. It won't read the If statement 

any help would be appreciated :D