public partial class adminmofiy : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
      
            string str = ConfigurationSettings.AppSettings["dsn"];
            SqlConnection cn = new SqlConnection(str);
            cn.Open();
            int straid = 0;
            if (Request.QueryString["aid"] != null)
            {
               straid = Convert.ToInt32(Request.QueryString["aid"].ToString());
            }
            else
            {
                Response.Write("对不起，没有该人员信息");
                Response.End();
            }
            string mysql = "SELECT * FROM admin WHERE (aid =" + straid + ")";
运行起来就显示“对不起，没有该人员信息”

我改了一下，aid这个字段是字符型的，可不知道怎么给aid赋值。
 string str = ConfigurationSettings.AppSettings["dsn"];
            SqlConnection cn = new SqlConnection(str);
            cn.Open();
            string straid = "";
            if (Request.QueryString["aid"] != null)
            {
               straid = Request.QueryString["aid"];
            }
            else
            {
                Response.Write("对不起，没有该人员信息");
                Response.End();
            }
            string mysql = "SELECT * FROM admin WHERE (aid =" + straid + ")";
            SqlCommand cm = new SqlCommand(mysql, cn);
            SqlDataReader dr = cm.ExecuteReader();

帮我改一下吧，帮帮忙吧