Public Class Form1
    Sub fillcombo()

        strsql = "select distinct * from Таблица1"
        Dim acscmd As New OleDb.OleDbCommand
        acscmd.CommandText = strsql
        acscmd.Connection = acsconn
        acsdr = acscmd.ExecuteReader
        While (acsdr.Read())
            ComboBox1.Items.Add(acsdr("Виконавці"))
        End While
        acscmd.Dispose()
        acsdr.Close()
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        strsql = "select DISTINCT Таблица1.Виконавці from Таблица1"

        Dim acscmd As New OleDb.OleDbCommand
        acscmd.CommandText = strsql
        acscmd.Connection = acsconn
        acsdr = acscmd.ExecuteReader

        acscmd.Dispose()
        acsdr.Close()
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Module1.connect()
        Me.fillcombo()
    End Sub
End Class