Select.Row in the datagridview is not working

I am recovering data when i select a row. It was working, but i did something that know is not working, i want know if have something that block this behavior in the properties in datagridview.

mycode:

UsuariosMensagens userMsg = new UsuariosMensagens();

userMsg = MsgDataGridView.CurrentRow.DataBoundItem as UsuariosMensagens;

var retorno = msgDal.RecuperaMensagemDetalhadaExibicao(userMsg);

if (retorno != null)
{
MensagemLabel.Text = retorno;
textBox1.Text = retorno;
}
else
{
string msgRetorno = ” ERRO retorno -> ” + retorno;
AlertBox.Show(msgRetorno);
}