The increase and deletion of ASP. NET MVC Ef-dbfirst

Controller and action method:

Using system;using system.collections.generic;using system.linq;using system.web;using System.Web.Mvc;using Mvc5test.models;using system.data.entity.infrastructure;namespace mvc5test.controllers{// The user's request is always first sent to an action method of the controller, and the corresponding view is returned by the action method public class Homecontroller:controller {//Data context object Bogent        Ities db = new bogentities (); Query article Public ActionResult Index () {//sqo standard query operator//dbquery<classtype> queries = d B.classtypes.where (ct = ct).            parentid==0) as dbquery<classtype>; List<classtype> ctlist = db. Classtype.where (ct = ct). ParentID = = 0).            Tolist<classtype> (); Linq list<artical> alist = (from a in db. artical where A.classtypeid! = 4 Select a).            ToList ();            Use ViewData to pass data to the view viewdata["alist"] = alist;        return View ();      }//delete article//the default parameter ID here App_start RouteConfig.cs config public actionresult Del (int id)  {try {//1. Create the object to be deleted artical A = new artical {id = id}; 2. Add the object to the EF Management container db.                Artical.attach (a); 3. Identify the state of the object wrapper class as Delete db.                Artical.remove (a); 4. Update Database DB.                SaveChanges ();            5. The update succeeds, the command browser jumps to the list page return redirecttoaction ("Index", "Home"); } catch (Exception e) {return Content ("Delete failed!!!            "+e.message);            }}//modify article-show action [HttpGet]//get request when executing the following method public ActionResult Edit (int id) { 1. Query the database by ID, return the first object in the collection artical a = (from at DB. artical where at.id = = ID select at).            FirstOrDefault (); 2. Generate the article Classification data drop-down list collection ienumerable<selectlistitem> selectlist = (from CT in db. ClassType Select CT). ToList ()//from DB.                ClassType the selection of elements in a collection to form a new set of CT                                      . Select (ct = new SelectListItem {Value = ct.id. ToString (), Text = Ct. ClassName}//Iterate through each element in the CT collection and turn each element that is traversed into a SelectListItem object).            ToList ();            Use ViewBag to pass data to view viewbag.ctlist = SelectList;        3. Pass the article to the view//*** use the view's construction method to pass the data to a property named model on the View Return view (a); }//Modify article-Save action [HttpPost]//post request when executing the following method public ActionResult Edit (artical model)//This time the model is the page to be modified The article entity object {try {//1. Add the Entity object to the EF object container and get the Pseudo wrapper class object Dbentityentry<a Rtical> entry = db.                Entry<artical> (model); 2. Set the state of the wrapper class object to unchanged entry.                state = System.Data.Entity.EntityState.Unchanged; 3. Set the changed attribute entry. Property (A = A.title).                IsModified = true; Entry. Property (A = A.classtypeid).                IsModified = true; //4. Commit to the database and complete the change db.                SaveChanges ();            5. The update succeeds, then the command browser redirects to the list page return redirecttoaction ("Index", "Home"); } catch (Exception e) {return Content ("Modify failed!!!            "+e.message);            }}//new article-Show action [httpget] public ActionResult Add () {//Generate article Category data drop-down list collection Ienumerable<selectlistitem> selectlist = (from CT in db. ClassType Select CT). ToList ()//from DB. The ClassType collection selects the elements to form a new set of Ct. Select (ct = new SelectListItem {Value = ct.id. ToString (), Text = Ct. ClassName}//Iterate through each element in the CT collection and turn each element that is traversed into a SelectListItem object).            ToList ();            Use ViewBag to pass data to view viewbag.ctlist = SelectList;        return View (); }//new article-Save action [HttpPost] public actionresult Add (artical moDel) {try {//1. Add the Entity object to the EF object container and get the Pseudo wrapper class object Dbentityentry<arti Cal> entry = db.                Entry<artical> (model); 2. Set the state of the wrapper class object to added entry.                state = System.Data.Entity.EntityState.Added; 3. Submit to the database to complete the new db.                SaveChanges ();            4. The update succeeds, then the command browser redirects to the list page return redirecttoaction ("Index", "Home"); } catch (Exception e) {return Content ("New failed!!!            "+ e.message); }        }    }}

First page Data list view:

@using mvc5test.models;@{Layout = null;} 
 New View: 
 
@model Mvc5Test.Models.Artical @{Layout = null;} <! DOCTYPE html>
 Edit view: 
 
@model Mvc5Test.Models.Artical <!--The above code is the type of the specified page model property-->@{Layout = null;} <! DOCTYPE html>
　　
The increase and deletion of ASP. NET MVC Ef-dbfirst