运行更新查询但在C＃中没有更新 [英] run update query but no update in C#

问题描述

这是我的数据库更新代码

当我运行这个没有错误但数据库没有更新仍然相同的价格

  string  c_time = DateTime.Now.ToString（  HH：mm：ss tt）; 
  string  c_date = DateTime.Today.ToString（  DD-MM-YYYY）; 
 
 使用（SqlConnection conn =  new  SqlConnection（ @  Data Source = MCK-PC\MCKSQL; Initial Catalog = my_db; Integrated Security = True））
 {
 SqlCommand newCmd =  new  SqlCommand（ @  UPDATE emp SET last_act_date = @ last_act_date，last_act_time = @ last_act_time WHERE Card_no = @ Card_no;，conn）; 
 
 newCmd.Parameters.AddWithValue（  @ last_act_date，c_date）; 
 newCmd.Parameters.AddWithValue（  @ last_act_time，c_time）; 
 newCmd.Parameters.AddWithValue（  @ Card_no，card_no_input.ToString（））; 
 
 ConnectionState state = conn.State; 
  if （state == ConnectionState.Closed）
 {
 newCmd.Connection.Open（）; 
 newCmd.ExecuteNonQuery（）; 
 newCmd.Connection.Close（）; 
} 
 
  else  
 {
 newCmd.ExecuteNonQuery（）; 
 newCmd.Connection.Close（）; 
} 
 
} 

感谢提前！

解决方案

检查 card_no_input - 这听起来像是某种输入，所以有一个商品机会你想要它的Text属性而不是调用ToString 。



如果它是一个TextBox，你的查询将尝试更新卡号为System.Forms.TextBox或类似的所有记录

This is my database update code
when i run this no errors but database not updated still same vales

string  c_time= DateTime.Now.ToString("HH:mm:ss tt");
string  c_date= DateTime.Today.ToString("dd-MM-yyyy");

using (SqlConnection conn = new SqlConnection(@"Data Source=MCK-PC\MCKSQL;Initial Catalog=my_db;Integrated Security=True"))
 {
   SqlCommand newCmd = new SqlCommand(@"UPDATE emp SET last_act_date=@last_act_date , last_act_time=@last_act_time WHERE Card_no=@Card_no;", conn);

   newCmd.Parameters.AddWithValue("@last_act_date", c_date);
   newCmd.Parameters.AddWithValue("@last_act_time", c_time);
   newCmd.Parameters.AddWithValue("@Card_no", card_no_input.ToString());

   ConnectionState state = conn.State;
   if (state == ConnectionState.Closed)
     {
       newCmd.Connection.Open();
       newCmd.ExecuteNonQuery();
       newCmd.Connection.Close();
     }

   else
     {
       newCmd.ExecuteNonQuery();
       newCmd.Connection.Close();
     }

 }

THANK IN ADVANCE!

解决方案

Check card_no_input - it sounds like it's an input of some kind, so there is a goods chance that you want it's Text property rather than calling ToString.

If it is a TextBox for example, your query will be trying t to update all records where the card number is "System.Forms.TextBox" or similar

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