you need to use return dataset of your method
private void button2_Click(object sender, EventArgs e)
{
dataGridView1.DataSource = llenarDataSet().Tables[0];;
}
in your
button1_Click
, you call
llenarDataSet
but never used returned value of that method. you need to keep that value in form field or property, if you going to use it on another event. in your button2_Click what you are doing is creating new DataSet and assigning it as datasource. there is no data in new DataSet. you will get empty gridview at the end.