The function implementation code of chapter 4 of the MVC4 website tutorial, and chapter 4 of mvc4

The function implementation code of chapter 4 of the MVC4 website tutorial, and chapter 4 of mvc4

Collation
I. Users
Ii. User Group
Iii. Topic
3.1 Add a topic
3.2 browse topic
3.3 update topic
3.4 delete a topic
3.5 foreground topic browsing
......
Topic model;

The model should have the following fields: column name, parent column id, column type, content model, column view, content view, link address, and column sorting. For the time being, I think so much about it first.

The topic name and parent topic id are not to mention easy.

There are three types of columns: Common columns-General columns; single-page columns-a column is a page, such as a company introduction or contact address; external link: click a column to jump to a link.

Content Model-refers to the content of a common topic, such as news, articles, and messages.

Topic view-is the view name used by the topic. It is invalid when the topic type is Link.

Content view: it refers to the view of the specific content of a topic. When the topic model is news, the view used to open news under the topic is only valid when the topic type is normal.

Link address-click the address to jump to, which is valid when the column type is Link.

Column sorting-the basis for column sorting. The smaller the number of columns at the same level, the higher the ranking.

Right-click the Models folder and choose "add Category ".

Using System. componentModel. dataAnnotations; namespace Ninesky. models {/// <summary> /// topic model /// </summary> public class Category {[Key] public int CategoryId {get; set ;} /// <summary> /// topic Name /// </summary> [Display (Name = "topic Name", Description = "2-20 characters")] [Required (ErrorMessage = "×")] [StringLength (20, MinimumLength = 2, ErrorMessage = "×")] public string Name {get; set ;} /// <summary> /// parent column No. /// </ Summary> [Display (Name = "parent")] [Required (ErrorMessage = "×")] public int ParentId {get; set ;} /// <summary> /// topic type [0-common topic; 1-single-page topic; 2-external link] /// </summary> [Display (Name = "topic Type")] [Required (ErrorMessage = "×")] public int Type {get; set ;} /// <summary> /// Content Model [effective only when the column is normal] /// </summary> [Display (Name = "Content Model")] public string Model {get; set ;}/// <summary> /// topic view /// </summary> [Display (Name = "Topic View", Description = "topic page view, which can contain a maximum of 255 characters .. ")] [StringLength (255, ErrorMessage =" × ")] public string CategoryView {get; set ;} /// <summary> /// content page view /// </summary> [Display (Name = "content View", Description = "Content Page View, it can contain a maximum of 255 characters .. ")] [StringLength (255, ErrorMessage =" × ")] public string ContentView {get; set ;} /// <summary> /// link address /// </summary> [Display (Name = "link address", Description = "link address to jump to when you click a column, it can contain a maximum of 255 characters. ")] [StringLength (255, ErrorMessage =" × ")] public string Navigation {get; set ;} /// <summary> /// column sorting /// </summary> [Display (Name = "column sorting", Description = "the smaller the number, the higher the order. ")] Public int Order {get; set ;}}}

Add column type enumeration under the Category class

Public enum CategoryType {general topic, single-page topic, external link}

Open NineskyContext. cs and add the public DbSet <Category> Categorys {get; set;} code above. The file is as follows :.

using Ninesky.Models;using System.Data.Entity;namespace Ninesky.Repository{  public class NineskyContext:DbContext  {    public DbSet<User> Users { get; set; }    public DbSet<UserGroup> UserGroups { get; set; }    public DbSet<Category> Categorys { get; set; }    public NineskyContext()      : base()    {      Database.CreateIfNotExists();    }  }}

Add the CategoryRepository class to the Repository folder. This class inherits from the RepositoryBase <Category> class, and write functions such as add, delete, modify, and search in the class. Complete the following steps:

Using System; using System. collections. generic; using System. linq; using System. web; using Ninesky. models; namespace Ninesky. repository {public class CategoryRepository: repositoryBase <Category >{/// <summary> /// Add a topic /// </summary> /// <param name = "category"> topic </param>/ // <returns> </returns> public override bool Add (Category category) {dbContext. categorys. add (category); if (dbContext. saveChanges ()> 0) return true; else return false ;} /// <summary> /// update the topic /// </summary> /// <param name = "category"> topic </param> /// <returns> </returns> public override bool Update (Category category) {dbContext. categorys. attach (category); dbContext. entry <Category> (category ). state = System. data. entityState. modified; if (dbContext. saveChanges ()> 0) return true; else return false ;} /// <summary> /// delete a topic /// </summary> /// <param name = "category"> topic </param> /// <returns> </returns> public bool Delete (Category category) {dbContext. categorys. remove (category); if (dbContext. saveChanges ()> 0) return true; else return false ;} /// <summary> /// delete a topic /// </summary> /// <param name = "CategoryId"> topic Id </param> /// <returns> </returns> public override bool Delete (int CategoryId) {var _ category = dbContext. categorys. singleOrDefault (c => c. categoryId = CategoryId); if (_ category = null) return false; else return Delete (_ category );} /// <summary> /// search for a specific topic /// </summary> /// <param name = "CategoryId"> topic id </param> /// <returns> </returns> public override Category Find (int CategoryId) {return dbContext. categorys. singleOrDefault (c => c. categoryId = CategoryId );} /// <summary> /// obtain the followed topic /// </summary> /// <returns> </returns> public IQueryable <Category> Root () {return Children (0 );} /// <summary> /// obtain the subtopic /// </summary> /// <param name = "CategoryId"> topic Id </param> /// <returns> </returns> public IQueryable <Category> Children (int CategoryId) {return dbContext. categorys. where (c => c. parentId = CategoryId ). orderBy (c => c. order );} /// <summary> /// column list /// </summary> /// <param name = "model"> model name </param> /// <returns> </returns> public IQueryable <Category> List (string model) {return dbContext. categorys. where (c => c. model = model ). orderBy (c => c. order );}}}

This is the time for preparation. OK!

The above is all the content of this article. I hope it will be helpful for your learning and support for helping customers.