Practical Approach to Learn MVC: Part 4

Here what I am doing is basically adding both of the properties here (Bind(Include = "Id,EmpName,Salary,Gender,MobileNo,EmailId,EmpDOB")) and the rest will be the same. Now run this view and you can now add a mobile number and email id using this view.

In the same way you can edit the Edit view also with the preceding procedure. In the edit view you must do something with [Bind(Include = "Id,EmpName,Salary,Gender,MobileNo,EmailId,EmpDOB")] in the controller method decorated with [HttpPost] and Delete and Details. You just must add a label. For a better understanding download the code.

In the preceding example we saw how to add properties inside the Employee class. What happens if we want to create a new department and establish a one-to-many relationship with the Department and Employee tables? Let's see it with an example.

We need to go through following procedure to add new table and defend the relationship with them.

Go to employee class and add another class Department like follows.

Note: Here if you not write [ForeignKey("Department")] public int DeptId { get; set; } then also foreign key relationship will be created but the name of that foreign key field will be default name given by the Entity Framework. The preceding line will just change the default name of the foreign key to DeptId.

When both class is ready go to EmployeeDBContext and add the DbSet<Departments> there like:

The preceding method will execute when model will be creating. You need to add following name spaces also;

Build the project and go to Configuration.cs asn modify the default list by using following code.

If you did not make these AutomaticMigrationsEnabled = true; AutomaticMigrationDataLossAllowed = true; properties true then there must be an error.

Then build the project and go to Package Manager Console and run following command.

That it run the project all the tables with defined relationship will be created check that in SQL Server. Now we need to modify the views and controller action method. If you want to modify it manually you can here I am just dropping the Employee controller and employees view folder and recreating it. In last session I have explained how to create controller and views if you are new to it just go through that first.

Now run the project and try to navigate the Index view of the employees controller or you can open the Index view by clicking Views folder and going to employees folder and clicking to Index.cshtml and then press ctrl+F5.

Here notice the design of the view. It has been change automatically. The Entity Framework is smart enough for creating the views based on the structure of the database table and controller action method.

Note: Note I have mark virtual ICollections<> for the property to create relationship this is because

Lazy Loading: Any virtual ICollections will be lazy-loaded unless you specifically mark them otherwise.

If you meet all the following requirements then your change tracking can use a more efficient method by hooking your virtual properties.

To get change tracking proxies, the basic rule is that your class must be public, non-abstract or non-sealed. Your class must also implement public virtual getters/setters for all properties that are persisted. Finally, you must declare collection based relationship navigation properties as ICollection<T> only. They cannot be a concrete implementation or another interface that derives from ICollection<T> (a difference from the Deferred Loading proxy)

If you are new to create relationship in Entity Framework code first approach click here for detail.

That's it for today. In our next session we will discuss how to customize these views depending on our need.

In this illustration you came to understand the basics of the MVC Model and how to modify the database table and defend the relationship among those tables using the Entity Framework Code First Approach.

Thanks.

I would like to get feedback from my readers. Please post your feedback, question, or comments about this article.