我正在使用json在Asp.net MVC中创建一个简单的Crud系统。我需要更新记录。但是我不怎么做。我成功地查看了数据库中的数据并将其传递给Datatable。并成功添加记录。当我编辑记录时，我不知道如何从控制器传递值，到目前为止我在下面写的内容。Edit（int Id）我只是这样尝试。数据没有传递到相关的文本框进行编辑。
public class HomeController : Controller
{
// GET: /Home/
public ActionResult Index()
{
return View();
}
lgschoolEntities1 dc = new lgschoolEntities1();
public ActionResult GetStudents()
{
using (lgschoolEntities1 db = new lgschoolEntities1())
{
var student = db.courses.ToList();
return Json(new { data = student }, JsonRequestBehavior.AllowGet);
}
}
[HttpPost]
public ActionResult Save(course cou)
{
bool status = false;
if (ModelState.IsValid)
{
using (lgschoolEntities1 dc = new lgschoolEntities1())
{
if (cou.id > 0)
{
//Edit
var v = dc.courses.Where(a => a.id == cou.id).FirstOrDefault();
if (v != null)
{
v.name = cou.name;
v.course1 = cou.course1;
}
}
else
{
//Save
dc.courses.Add(cou);
}
dc.SaveChanges();
status = true;
}
}
return new JsonResult { Data = new { status = status } };
}
[HttpGet]
public ActionResult Edit(int Id)
{
//Get the student from studentList sample collection for demo purpose.
//Get the student from the database in the real application
var std = dc.courses.Where(a => a.id == Id).FirstOrDefault();
return new JsonResult { Data = new { std = std } };
}
在我编写的用于查看数据库中记录的代码下面。当我查看记录时，如果要编辑记录，请单击“编辑”按钮，相关数据将传递到相关的textbooxs进行编辑。
function get_all() {
$('#tbl-category').dataTable().fnDestroy();
var oTable = $('#tbl-category').DataTable({
"ajax": {
"url": '/home/GetStudents',
"type": "get",
"datatype": "json"
},
"columns": [
{ "data": "name", "200px": true },
{ "data": "course1", "200px": true },
{
"data": "id", "width": "50px", "render": function (data) {
return '<button class="btn btn-xs btn-success" onclick="get_category_details(' + data + ') ">Edit</button>';
}
},
{
"data": "id", "width": "50px", "render": function (data) {
return '<button class="btn btn-xs btn-primary" onclick="RemoveCategory(' + data + ')">Delete</button>';
}
}
]
})
}
我正在同时执行添加和编辑操作。
function addProject() {
var _url = '';
var _data = '';
var _method;
if (isNew == true) {
_url = '/home/Save';
_data = "{name: '" + $('#name').val() + "',course1: '" + $('#course1').val() + "'}";
_method = 'POST';
}
else {
_url = '/home/Edit',
// _data = "{fname: '" + $('#fname').val() + "',age: '" + $('#age').val() + "', id: '" + id + "'}";
_data = "{fname: '" + $('#fname').val() + "', age: '" + $('#age').val() + "', id:'" + ID + "'}";
_method = 'POST';
}
console.log(_data);
$.ajax({
type: _method,
url: _url,
dataType: 'JSON',
contentType: "application/json; charset=utf-8",
data: _data,
success: function (data) {
alert("Success");
get_all();
$('#name').val("");
$('#course1').val("");
$('#name').focus();
var msg;
if (isNew) {
msg = "Data Created";
}
else {
msg = "Update Created";
}
$.alert({
title: 'Success!',
content: msg,
type: 'green',
boxWidth: '400px',
theme: 'light',
useBootstrap: false,
autoClose: 'ok|2000'
});
}
});
}
这是我单击编辑按钮时如何将值传递到相关文本框的方法。
function get_category_details(id) {
$.ajax({
type: 'POST',
url: '/home/Edit',
dataType: 'JSON',
data: "{id: '" + id + "'}",
contentType: "application/json; charset=utf-8",
success: function (data) {
console.log(data);
// $('body').animate({ scrollTop: 0 }, 1000);
isNew = false;
ID = data.d[0].id;
$('#id').attr('value', data.d[0].id);
$('#name').attr('value', data.d[0].name);
$('#course1').attr('value', data.d[0].course1);
}
});
}
表格
<div class="row">
@using (Html.BeginForm("save","home", FormMethod.Post, new { id= "popupForm" }))
{
<div class="card-panel teal lighten-2 white-text" align="center">
<h4> Registation</h4>
</div>
<div class="card-action">
<label class="form-label">Name</label>
<input type="text" id="name" name="name" class="form-control" placeholder="Name" required />
</div>
<div class="card-action">
<label class="form-label">Course</label>
<input type="text" id="course1" name="course1" class="form-control" placeholder="Course" required />
</div>
<div class="card" align="center">
<button type="button" id="save" class="btn btn-info" onclick="addProject()">
Registation
</button>
</div>
}
</div>
<div class="col s12 m6 offset-m4">
<div class="panel-heading">
<h3 class="panel-title">Current Team Members</h3>
</div>
<div class="panel-body">
<table id="tbl-category" style="width:90%; margin:0 auto">
<thead>
<tr>
<th>Name</th>
<th>Course</th>
<th>Edit</th>
<th>Delete</th>
</tr>
</table>
</div>
</div>
这是我断点时显示的错误
答案 0 :(得分：1)
您已经做对了，只是需要告诉Entity Framework模型已更改，您可以通过设置模型状态，将状态更改为EntityState.Modified
如下所示
[HttpPost]
public ActionResult Save(course cou)
{
bool status = false;
if (ModelState.IsValid)
{
using (lgschoolEntities1 dc = new lgschoolEntities1())
{
if (cou.id > 0)
{
//Edit
var v = dc.courses.Where(a => a.id == cou.id).FirstOrDefault();
if (v != null)
{
v.name = cou.name;
v.course1 = cou.course1;
//you just need to add this line
dc.Entry(v).State = EntityState.Modified;
}
}
else
{
//Save
dc.courses.Add(cou);
}
dc.SaveChanges();
status = true;
}
}
return new JsonResult { Data = new { status = status } };
}
在进行dc.Entry(v).State = EntityState.Modified;时，不仅将实体附加到数据库上下文，还将整个实体标记为脏的并且已更新。这意味着当您执行context.SaveChanges（）时，EF将生成一条更新语句，该语句将更新实体的所有字段。
所以编辑也意味着更新Db中的记录
还要查看一些详细信息here
编辑 还要将javascript函数更改为
function addProject() {
var _url = '';
var _data = '';
var _method;
if (isNew == true) {
_url = '/home/Save';
_data = "{name: '" + $('#name').val() + "',course1: '" + $('#course1').val() + "'}";
_method = 'POST';
}
else {
_url = '/home/Save', //Change this line because you are using thte same method to save and edit in your controller
// _data = "{fname: '" + $('#fname').val() + "',age: '" + $('#age').val() + "', id: '" + id + "'}";
_data = "{fname: '" + $('#fname').val() + "', age: '" + $('#age').val() + "', id:'" + ID + "'}";
_method = 'POST';
}
console.log(_data);
//You ajax call here
//The code below was commented to keep answer short
}
[HttpGet] //Change to get
public JsonResult Edit(int Id)
{
return new JsonResult { Data = new { std = std } };
}
还可以更改您在javascript中调用它的方式以及分配变量的方式
function get_category_details(id) {
$.ajax({
type: 'GET',
url: '/home/Edit?Id=' + id,
dataType: 'JSON',
contentType: "application/json; charset=utf-8",
success: function (data) {
console.log(data);
// $('body').animate({ scrollTop: 0 }, 1000);
isNew = false;
ID = data.id;
$('#id').val(data.id);
$('#name').val(data.name);
$('#course1').val(data.course1);
}
});
}