private void _okButton_Click(object sender, RoutedEventArgs e)
{
var digitalSignature = _signatureComboBox.SelectedItem as DigitalSignature;
int limit = 0;
if (!Inspect.ContainTrustSignature(digitalSignature.ToString())) limit = -1;
var comment = _commentTextBox.Text.Substring(0, Math.Min(_commentTextBox.Text.Length, Message.MaxCommentLength));
var message = new Message(comment);
_amoebaManager.MulticastUpload(_tag, message, limit, Settings.Instance.Global_MiningTime, digitalSignature);
this.Close();
}