In button click event write the following code:
Before that create static int i=0; in the global declaration part;
{
SqlConnection con = new SqlConnection(@"Data Source=ATTRES-3BC2A6\SQLEXPRESS;Initial Catalog=harsha;Integrated Security=True");
SqlDataAdapter da = new SqlDataAdapter("select * from Exam )", con);
da.Fill(ds, "Exam");
dt = ds.Tables["Exam"];
i = dt.Rows.Count;
dr = dt.Rows[i];
Label1.Text = dr[0].ToString();
RadioButton1.Text = dr[1].ToString();
RadioButton2.Text = dr[2].ToString();
RadioButton3.Text = dr[3].ToString();
RadioButton4.Text = dr[4].ToString();
i++;
}
For each click you will get a differnt question from your database.
Hope this is useful for you.