private void OnAddEditContactRequestMsg(AddEditContactRequestMsg obj)
        {
            var openFileDialog = new OpenFileDialog { DefaultExt = "key", Filter = "Public Key File (*.key)| *.key" };
            var dialogResult = openFileDialog.ShowDialog();

            if (dialogResult != null && dialogResult.Value)
            {
                var filename = openFileDialog.FileName;
                _messenger.Send(new AddEditContactConfirmMsg(filename));
            }
        }
        private void OnAddEditContactRequestMsg(AddEditContactRequestMsg obj)
        {
            var openFileDialog = new OpenFileDialog {
                DefaultExt = "key", Filter = "Public Key File (*.key)| *.key"
            };
            var dialogResult = openFileDialog.ShowDialog();

            if (dialogResult != null && dialogResult.Value)
            {
                var filename = openFileDialog.FileName;
                _messenger.Send(new AddEditContactConfirmMsg(filename));
            }
        }