[Visual Basic]
   Private Sub btnsearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnsearch.Click
        IMC.BeginSearchUsers(txtusername.Text, txtfirstname.Text, txtlastname.Text, txtemail.Text, cbonline.Checked)
    End Sub

[Visual Basic]

    Delegate Sub DelegateOnSearchUsersCompleted(ByVal Usernames As String)
    Private Sub IMC_OnSearchUsersCompleted(ByVal Usernames As String) Handles oMC.OnSearchUsersCompleted

        Dim NewFriDlg As New DelegateOnSearchUsersCompleted(AddressOf addItems)
        Me.BeginInvoke(NewFriDlg, Usernames)

    End Sub

    Private Sub addItems(ByVal Usernames As String)
        lbusers.Items.Clear()

        Dim uns As String() = Usernames.Split(",")
        For i As Integer = 0 To UBound(uns)
            If uns(i).Trim <> "" Then
                lbusers.Items.Add(uns(i))
            End If

        Next
    End Sub