c#中用textbox输出一个数据库查询结果

Question

C#：如何实现：在textbox中显示SQLsever数据库中查询（例如;select grade from student where sno=121101)所得的一个数据？
求大神帮忙啊！！！

Answer 1

 using(SqlConnection conn = new SqlConnection("server=.;uid=sa;pwd=123456;database=yourdb"))
{
  conn.Open();

  SqlCommand cmd = new SqlCommand("select grade from student where sno = 121101",conn);

  object obj = cmd.ExecuteScalar();
  if(obj!=null)
  {
    this.textbox1.Text = obj.ToString();
  }
}