Question

我有以下代码，而且它没有更新数据库。代码正在执行它想要做的事情，但是当我执行NonQuery（）时，它不会将任何内容保存回数据库。连接字符串没问题，因为它对于正在运行的选择查询是相同的。

    const string str = @"Data Source=localhost;Initial Catalog=Items;Integrated Security=True";
        static void Main(string[] args)
        {
            const string connectionString = str;

            DataTable DataTableAllWithoutID = new DataTable();
#if !test
            string queryString = "select * from table_items_shelves;";
            SqlDataAdapter adapterAllWithoutID = new SqlDataAdapter(queryString, connectionString);
            adapterAllWithoutID.Fill(DataTableAllWithoutID);
            adapterAllWithoutID.Dispose();
            SqlConnection connection = new SqlConnection(connectionString);
            connection.Open();
            string insertString = "Update table_items_shelves Set Item_ID = @Item_ID where Item_Name = '@key';";
            SqlCommand insertCommand = new SqlCommand(insertString, connection);
            insertCommand.Parameters.Add("@Item_ID", SqlDbType.Int);
            insertCommand.Parameters.Add("@key", SqlDbType.NVarChar);
#else
            DataTableAllWithoutID.Columns.Add("Item_Name", typeof(string));
            DataTableAllWithoutID.Columns.Add("Item_ID", typeof(object));
            foreach (List<object> row in input)
            {
                DataRow newRow = DataTableAllWithoutID.Rows.Add();
                newRow.ItemArray = row.ToArray();
            }

#endif
            //this code will get empty items
            List<DataRow> nullOrEmpty = DataTableAllWithoutID.AsEnumerable()
               .Where(x => x.Field<object>("Item_ID") == null)
               .ToList();
            //this creates a dictionary of valid items
            Dictionary<int, List<DataRow>> dict = DataTableAllWithoutID.AsEnumerable()
                .Where(x => x.Field<object>("Item_ID") != null)
                .GroupBy(x => x.Field<object>("Item_ID"), x => x)
                .ToDictionary(x => Convert.ToInt32(x.Key), x => (List<DataRow>)x.ToList());
            //create IEnumerator for the null items
            IEnumerator<DataRow> emptyRows = nullOrEmpty.GetEnumerator();
            Boolean noMoreEmptyRows = false;
            if (emptyRows != null)
            {
                foreach (int key in dict.Keys)
                {
                    Console.WriteLine(key.ToString());
                    //get count of items            
                    int count = dict[key].Count;
                    int itemID = (int)key;
                    for (int index = count; count < 8; count++)
                    {
                        if (emptyRows.MoveNext())
                        {
                            //get an item from the null list                  
                            emptyRows.Current["Item_ID"] = itemID;
                            insertCommand.Parameters["@Item_ID"].Value = itemID;
                            insertCommand.Parameters["@key"].Value = emptyRows.Current["Item_Name"];
                            insertCommand.ExecuteNonQuery();
                            Console.WriteLine("current item ID " + itemID);
                            Console.WriteLine("current count " + count);
                            //Console.ReadKey();
                        }//end if
                        else
                        {
                            noMoreEmptyRows = true;
                            break;
                        }//end else
                    }//end for
                    if (noMoreEmptyRows)
                        break;
                }//end foreach
                if (!noMoreEmptyRows)
                {
                    //increment key to one greater than max value
                    int maxKey = dict.Keys.Max() + 1;
                    int count = 0;
                    while (emptyRows.MoveNext())
                    {
                        //get an item from the null list                  
                        emptyRows.Current["Item_ID"] = maxKey.ToString();
                        insertCommand.Parameters["@Item_ID"].Value = maxKey.ToString();
                        insertCommand.Parameters["@key"].Value = emptyRows.Current["Item_ID"];

                            insertCommand.ExecuteNonQuery();

                          count++;
                        if (count == 8)
                        {
                            maxKey++;
                            count = 0;
                        }
                    }
                }
            }//end if
#if test
            foreach (DataRow row in DataTableAllWithoutID.Rows)
            {
                Console.WriteLine("Item_Name : {0}  Item ID :   {1}", 
                    row["Item_Name"], row["Item_ID"]);
            }
#endif

            FIllGroupID(str);
            Console.ReadKey();

        }

Answer 1

where Item_Name = '@key';

这是文字'@key' - 不参数@key的匹配项。你可能想要：

where Item_Name = @key;

C＃ExecuteNonQuery不更新数据库

1 个答案: