Question

public void ModificaNomeUtente(int slipno , int basicprice , int premium, int totalamountpaid, int weight , int totalamountbasic , int totalamountpremium , int yeildestimates , int farmercode)
        {
            // Creo la stringa di Connessione al DataBase 
            SqlConnection sqlConn = new SqlConnection(@"Data Source=TANYA-PC;Initial Catalog=biore1;Integrated Security=True");

            // Prova 
            try
            {
                // Creo la query che andrà a modificare il nome utente 
                string sqlQuery = "UPDATE cottonpurchse SET slipno = '" + slipno + "' + basic price = '" + basicprice + "' + premium = '" + premium  + "' + totalamountpaid = '" + totalamountpaid + "' + weight = '" + weight + "' + totalamountbasic = '" + totalamountbasic + "' + totalamountpremium = '" + totalamountpremium + "' + yeildestimated = '" + yeildestimates + "' =  WHERE  farmercode  = '" + FarmerCode + "'";
                SqlCommand cmd = new SqlCommand(sqlQuery, sqlConn);
                // Apro la connessione con il DataBase Login.sdf  
                sqlConn.Open();
                // Eseguo l'istruzione sql 
                cmd.ExecuteNonQuery();
                // Chiudo la connessione con il DataBase Login.sdf 
                sqlConn.Close();
                // Se la query ha avuto esito positivo imposto la variabile result a true 
                result = true;
            }


            // In caso di eccezzione  
            catch (Exception ex)
            {
                // Visualizzo il messaggio con la relativa eccezzione verificatasi 
                MessageBox.Show(ex.Message);
                // Chiudo la connessione con il DataBase Login.sdf 
                sqlConn.Close();
                // la query ha avuto esito negativo imposto la variabile result a false 
                result = false;
            }

            finally
            {
                // Chiudo la connessione con il DataBase Login.sdf 
                sqlConn.Close();
            }
        }

这不起作用它不更新可能是因为我的值被设置为null？

Answer 1

该陈述解析为类似的东西;

UPDATE cottonpurchse 
SET slipno = '???' + basic price = '???' + premium = '???' + totalamountpaid = '???' + weight = '???' + totalamountbasic = '???' + totalamountpremium = '???' + yeildestimated = '???' =  WHERE  farmercode  = '???'

=之前有WHERE这是非法的，您的意思是,而非+ ?

UPDATE cottonpurchse 
SET slipno = '???' , basic price = '???' , premium = '???' , totalamountpaid = '???' , weight = '???' , totalamountbasic = '???' , totalamountpremium = '???' , yeildestimated = '???'  WHERE  farmercode  = '???'

Answer 2

更新：每个人的评论都有效。你的SQL充满了错误：额外的空格，额外的+和额外的=。你是在混淆自己试图建立一个字符串......

那就是说，你的SQL查询字符串应该是这样的：

string sqlQuery = "UPDATE cottonpurchse SET slipno=" + slipno + ", basicprice=" + basicprice + ", premium=" + premium  + ", totalamountpaid=" + totalamountpaid + ", weight=" + weight + ", totalamountbasic=" + totalamountbasic + ", totalamountpremium=" + totalamountpremium + ", yeildestimated=" + yeildestimates + " WHERE farmercode=" + FarmerCode;

这是令人困惑的，因为你正在建立一个字符串。执行您尝试执行的操作的最佳（也是最安全）方法是使用SQL参数。请参阅：c# Sqlcommand error（特别是显示“Parameters.Add”的答案）

更新值

2 个答案: