当我在绑定gridview之前访问数据库时，gridview再也不会在这里绑定一些代码：
void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
date.Date = DateTime.Now;
string mode = Request.Params["mode"].ToString().ToLowerInvariant();
lblPatientName.Text= Session["PatientName"].ToString();
switch (mode)
{
case "new":
{
Page.Title = "Add New Patient Visit";
Session["visitID"] = System.Guid.NewGuid();
//get basic data (countrycode,cityCode,districtCode,areaCode) from patientdata table
SqlParameter pra = new SqlParameter("@Patientid", Session["PatientID"].ToString());
SqlDataReader dr = SqlHelper.ExecuteReader(ConfigurationManager.ConnectionStrings["NetCareConnectionString"].ConnectionString,
"PatientPrescriptionInsertPrepare", pra);
if (dr.Read())
{
SqlParameter[] prm = new SqlParameter[7];
prm[0] = new SqlParameter("@visitID", Session["visitID"].ToString());
prm[1] = new SqlParameter("@Patientid", Session["PatientID"].ToString());
prm[2] = new SqlParameter("@Specialization", Session["special"].ToString());
prm[3] = new SqlParameter("@countrycode", dr["CountryCode"].ToString());
prm[4] = new SqlParameter("@cityCode", dr["CityCode"].ToString());
prm[5] = new SqlParameter("@districtCode", dr["DistrictCode"].ToString());
prm[6] = new SqlParameter("@areaCode", dr["AreaCode"].ToString());
SqlHelper.ExecuteNonQuery(CommandType.StoredProcedure, "PreparePrescrption", prm);
}
}
break;
}
}
}
当我使用事件绑定网格时，当我删除上面的代码时，一切都运行良好：
protected void btnAdd_Click(object sender, EventArgs e)
{
SqlParameter [] prm = new SqlParameter[3];
prm[0] = new SqlParameter("@visitID", Session["visitID"].ToString());
prm[1] = new SqlParameter("@Patientid", Session["PatientID"].ToString());
prm[2] = new SqlParameter("@examinationcode", Session["Examinationcode"].ToString());
SqlHelper.ExecuteNonQuery(CommandType.StoredProcedure, "PatientExaminations_insert", prm);
gvParientInvs.DataBind();
}