ComboBox и БД

Imports System.Data.SqlServerCe
Public Class Form1
 
    Dim db As New SqlCeConnection("Data Source=D:\Exp\bd.sdf")
    Dim comand As SqlCeCommand
    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        Try
            ComboBox2.Items.Clear()
            If ComboBox1.SelectedIndex = 0 Then
                Fill_CB21()
            Else
                Fill_CB22()
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub
 
    Private Sub Fill_CB21()
        ComboBox2.Text = "Продавцы"
        Dim Select1 As String = "SELECT name FROM Market WHERE status='Seller'"
        comand = New SqlCeCommand(Select1, db)
        db.Open()
        Dim sqlReader As SqlCeDataReader = comand.ExecuteReader()
        Dim i As Integer = 0
        Do While sqlReader.Read()
            ComboBox2.Items.Add(sqlReader.GetString(0))
            i = i + 1
        Loop
        db.Close()
    End Sub
    Private Sub Fill_CB22()
 
        ComboBox2.Text = "Покупатели"
        Dim Select1 As String = "SELECT name FROM Market WHERE status='Buyer'"
        comand = New SqlCeCommand(Select1, db)
        db.Open()
        Dim sqlReader As SqlCeDataReader = comand.ExecuteReader()
        Dim i As Integer = 0
        Do While sqlReader.Read()
            ComboBox2.Items.Add(sqlReader.GetString(0))
            i = i + 1
        Loop
        db.Close()
    End Sub
End Class