求查询代码

我想按照姓名查询考勤，不知道怎么写代码啊，
 protected void Button1_Click(object sender, EventArgs e)
    {
        string str = ConfigurationSettings.AppSettings["dsn"];
        SqlConnection cn = new SqlConnection(str);
        cn.Open();
        String mysql = "select * from kaoqin where uname=" +TextBox2.Text;
        SqlDataAdapter da = new SqlDataAdapter(mysql, cn);
        DataSet ds = new DataSet();
        da.Fill(ds);
        GridView1.DataBind();
        cn.Close();
        
    }
求各位高手教我怎么写，