错误消息:对象引用未设置为对象的实例
本文关键字:对象 实例 设置 消息 对象引用 错误 | 更新日期: 2023-09-27 18:25:25
以下代码正在生成错误:
else if (period.ToString().Equals("3 years"))
{
for (int i = 0; i <= 36; i++)
{
string strCommandText5 = "INSERT INTO AutoTrans VALUES(@loanID,@transPeriod,null,@transStatus);";
SqlCommand myCommand5 = new SqlCommand(strCommandText5, myConnection);
myCommand5.Parameters.AddWithValue("@loanID", Session["@loanID"].ToString());
myCommand5.Parameters.AddWithValue("@transPeriod", numPeriod);
myCommand5.Parameters.AddWithValue("@transStatus", status);
numPeriod++;
myCommand5.ExecuteNonQuery();
}
}
错误消息:
对象引用未设置为对象的实例。在myCommand5.参数.AddWithValue("@loanID",Session["@loan ID"].ToString())上;
请帮我谢谢
按照更改代码
else if (period.ToString().Equals("3 years")&&Session["@loanID"]!=null)
{
for (int i = 0; i <= 36; i++)
{
string strCommandText5 = "INSERT INTO AutoTrans VALUES(@loanID,@transPeriod,null,@transStatus);";
SqlCommand myCommand5 = new SqlCommand(strCommandText5, myConnection);
myCommand5.Parameters.AddWithValue("@loanID", Session["@loanID"].ToString());
myCommand5.Parameters.AddWithValue("@transPeriod", numPeriod);
myCommand5.Parameters.AddWithValue("@transStatus", status);
numPeriod++;
myCommand5.ExecuteNonQuery();
}
}
Session["@loanID"]为空,请检查取消会话中的值:
if (Session["@loanID"] == null) { throw new Exception("Session["@loanID"] is null"); }
myCommand5.Parameters.AddWithValue("@loanID", Session["@loanID"].ToString());
错误不言自明,您的session
为空或null,这就是生成异常的原因。如果你想,用这个发送DbNull
myCommand5.Parameters.AddWithValue("@loanID", Session["@loanID"].ToString() ?? (object)DBNull.Value);