Question

我想在数据库中编辑这些数据并返回新数据
当我点击保存按钮时，数据不会改变这是控制器：

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Edit(CustomPerformancePerformersModel customPerformancePerformersModel)
    {
        if (ModelState.IsValid)
        {
            int perfromanceId = Convert.ToInt32(TempData.Peek("CurrentPerformanceId"));
            customPerformancePerformersModel.performanceObj = db.Performances.Where(x => x.PerformanceId == perfromanceId).FirstOrDefault();
            db.Entry(customPerformancePerformersModel.performanceObj).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
        }
        ViewBag.EventId = new SelectList(db.Events, "EventId", "Name", customPerformancePerformersModel.performanceObj.EventId);
        ViewBag.VenueId = new SelectList(db.Venues, "VenueId", "Name", customPerformancePerformersModel.performanceObj.VenueId);
        ViewBag.Performers = new SelectList(db.PerformerPerformances, "Performers", "Name", customPerformancePerformersModel.performanceObj.PerformerPerformances);
        return View(customPerformancePerformersModel.performanceObj);
    }

这是html：

   <div class="form-group">
        @Html.LabelFor(model => model.performanceObj.IsVisible, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            <div class="checkbox">
                @Html.EditorFor(model => model.performanceObj.IsVisible)
                @Html.ValidationMessageFor(model => model.performanceObj.IsVisible, "", new { @class = "text-danger" })
            </div>
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.performanceObj.IsFeatured, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            <div class="checkbox">
                @Html.EditorFor(model => model.performanceObj.IsFeatured)
                @Html.ValidationMessageFor(model => model.performanceObj.IsFeatured, "", new { @class = "text-danger" })
            </div>
        </div>

Answer 1

尝试以下方法：

# -*- coding: utf-8 -*-

#!/usr/bin/env python3

import paho.mqtt.client as mqtt
import os, json
import time
import configparser

# This is the Subscriber

settings = configparser.ConfigParser()
settings.read('VCAP_CONFIG.ini')

organization = settings['config']['org']
username = settings['config']['apikey']
password = settings['config']['authkey']


#Set the variables for connecting to the iot service
broker = ""
devicename = "007"
topic = "iot-2/type/DesktopApplication/id/007/evt/status/fmt/json"
#topic = 'iot-2/evt/status/fmt/json'
deviceType = "DesktopApplication"

clientID = "a:" + organization + ":appId"

print (clientID)

broker = organization + ".messaging.internetofthings.ibmcloud.com"
mqttc = mqtt.Client(clientID)

if username is not "":
 mqttc.username_pw_set(username, password=password)


def on_connect(client, userdata, flags, rc):
 print("Connected with result code "+str(rc))

def on_subscribe(mosq, obj, mid, granted_qos):
 print("Subscribed: " + str(mid) + " " + str(granted_qos))


def on_message(mosq, obj, msg):
    global message
    print(msg.topic + " " + str(msg.qos) + " " + str(msg.payload))

def on_message(client, userdata, msg):
     writeData = msg.payload.decode('utf-8')
     parsed_json = json.loads(writeData)
     UDD = parsed_json['UDD']
     DDD = parsed_json['DDD']
     PH = parsed_json['PH']
     Ignition = parsed_json['Ignition']

     # add the settings to the structure of the file, and lets write it out...
     config = configparser.ConfigParser()
     config['Data'] = {'UDD': UDD,
                      'DDD': DDD,
                      'PH': PH,
                  'Ignition':Ignition}
     with open('Data.ini', 'w') as configfile:
      config.write(configfile)

mqttc.connect(host=broker, port=1883, keepalive=60)
test = mqttc.subscribe(topic,0)

#print (test)
mqttc.on_connect = on_connect
mqttc.on_subscribe = on_subscribe
mqttc.on_message = on_message

mqttc.loop_forever()

Answer 2

理想情况下，您的代码将如下所示：

public ActionResult Edit(int performanceId)
{
    var model = db.Performances.FirstOrDefault(m => m.PerformanceId == performanceId);
    return View(model);
}

[HttpPost] //[HttpPatch] is technically correct, but most people I see tend to use only GET and POST actions.
[ValidateAntiForgeryToken]
public ActionResult Edit(CustomPerformancePerformersModel model)
{
    if (ModelState.IsValid)
    {
        db.Entry(model).State = EntityState.Modified;
        db.SaveChanges();
    }
}

您正在从数据库中检索对象并在GET操作中对其进行跟踪，使用您的表单对其进行修改，然后在更新操作中将其标记为已修改。如果您正在使用MVC模式，这是严格的，如果您使用单独的数据和视图模型，则会看起来不同（见下文）。如果您的视图没有模型中所有属性的字段（隐藏或不隐藏），您可能会遇到此方法的问题。

使用单独的数据和视图模型，您将拥有以下内容：

public ActionResult Edit(int performanceId)
{
    var performance = db.Performances.FirstOrDefault(m => m.PerformanceId == performanceId);
    var model = new PerformanceViewModel(performance); //In this constructor, copy properties from your data model to your view model
    return View(model);
}

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(PerformanceViewModel model)
{
    var performance = db.Performances.FirstOrDefault(m => m.PerformanceId == model.PerformanceId);
    model.Update(performance);
    db.SaveChanges();

}

使用示例视图模型：

public class PerformanceViewModel
{

    public PerformanceViewModel(CustomPerformanceePerformersModel model)
    {
        PerformanceId = model.performanceObj.PerformanceId;
        IsVisible = model.performanceObj.IsVisible;
        IsFeatured = model.performanceObj.IsFeatured;
    }
    public int PerformanceId { get; set; }

    public bool IsVisible { get; set; }

    public bool IsFeatured { get; set; }


    public void Update(CustomPerformancePerformersModel model)
    {
        model.performanceObj.IsVisible = IsVisible;
        model.performanceObj.IsFeatured = IsFeatured;
    }
}

在这里，您要创建一个单独的对象（视图模型），该对象仅包含视图所需的数据，然后使用该对象中的数据更新数据模型。我更喜欢这个，因为它能够有效地直接修改数据库，并且因为你可以在Update（Model）方法中进行任何必要的中间处理（将字符串转换为bool等）。

在mvc4中编辑没有用

2 个答案: