从数据库中获取数据并构建一个用于JSON的字符串
本文关键字:一个 用于 JSON 字符串 数据库 获取 数据 构建 | 更新日期: 2023-09-27 18:07:21
我想从数据库中返回所有数据并建立一个字符串,或者我想循环并将结果写入Json。
我的代码如下:public string GetNewTickets()
{
using (SqlConnection con = new SqlConnection(constr))
{
using (SqlCommand cmd = new SqlCommand("Select LoggedDate, count(ID) as ticketAmount from Tickets WHERE LoggedDate >=dateadd(day,datediff(day,0,GetDate())- 7,0) AND State = '1' group by LoggedDate"))
{
var ticketAmount = 0;
var loggedDate = DateTime.Now;
var ActualloggedDate = string.Empty;
var convertedLoggedDate = string.Empty;
var test = string.Empty;
cmd.Connection = con;
con.Open();
var reader = cmd.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
ticketAmount = (int)reader["ticketAmount"];
//Convert to JSON format
loggedDate = (DateTime)reader["LoggedDate"];
ActualloggedDate = JsonConvert.SerializeObject(loggedDate, new IsoDateTimeConverter());
convertedLoggedDate = ActualloggedDate.Substring(1, ActualloggedDate.Length - 4);
}
}
var entity = new
{
ticketAmount = ticketAmount,
loggedDate = convertedLoggedDate,
};
var json = serializer.Serialize(entity);
return json;
}
}
}
只返回json中的一行
{"ticketAmount":1,"loggedDate":"2016-09-16T08:03:"}
我的数据库中有大约10条记录,我想返回所有必要的记录。结果应该类似于
{"ticketAmount":1,"loggedDate":"2016-09-16T08:03:"},
{"ticketAmount":5,"loggedDate":"2016-09-17T08:03:"},
{"ticketAmount":4,"loggedDate":"2016-09-18T08:03:"}
如果您想返回多个JSON对象(每行一个),您可以返回一个JSON数组,如下所示:
[
{"ticketAmount":1,"loggedDate":"2016-09-16T08:03:"},
{"ticketAmount":5,"loggedDate":"2016-09-17T08:03:"},
{"ticketAmount":4,"loggedDate":"2016-09-18T08:03:"}
]
通过使用var json = serializer.Serialize(entity);
return json;
无论存在多少条匹配记录,您的程序都只序列化一个实体(最后一个)。因此,我建议将所有匹配的实体存储在List
中,并序列化List
对象。例句:
public class EntityDto {
public int ticketAmount {get; set;}
public DateTime loggedDate {get; set;}
}
...
public string GetNewTickets()
{
var entities = new List<EntityDto>();
using (SqlConnection con = new SqlConnection(constr))
{
using (SqlCommand cmd = new SqlCommand("Select LoggedDate, count(ID) as ticketAmount from Tickets WHERE LoggedDate >=dateadd(day,datediff(day,0,GetDate())- 7,0) AND State = '1' group by LoggedDate"))
{
var ticketAmount = 0;
var loggedDate = DateTime.Now;
var ActualloggedDate = string.Empty;
var convertedLoggedDate = string.Empty;
var test = string.Empty;
cmd.Connection = con;
con.Open();
var reader = cmd.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
ticketAmount = (int)reader["ticketAmount"];
//Convert to JSON format
loggedDate = (DateTime)reader["LoggedDate"];
ActualloggedDate = JsonConvert.SerializeObject(loggedDate, new IsoDateTimeConverter());
convertedLoggedDate = ActualloggedDate.Substring(1, ActualloggedDate.Length - 4);
var entity = new EntityDto
{
ticketAmount = ticketAmount,
loggedDate = convertedLoggedDate,
};
entites.Add(entity);
}
}
}
}
var json = serializer.Serialize(entities);
return json;
}