Part 17 - Editing a model in mvc

Suggested Videos 
Part 14 - Mapping asp.net request data to controller action simple parameter types
Part 15 - Updatemodel function in MVC
Part 16 - Difference between UpdateModel and TryUpdateModel



In this video we will discuss editing a model in mvc. Please watch Part 16, before proceeding.



Step 1: Copy and paste the following "Edit" controller action method in "EmployeeController.cs" file.
[HttpGet]
public ActionResult Edit(int id)
{
    EmployeeBusinessLayer employeeBusinessLayer = 
           new EmployeeBusinessLayer();
    Employee employee = 
           employeeBusinessLayer.Employees.Single(emp => emp.ID == id);
            
    return View(employee);
}

Please note:
1. This method is decorated with [HttpGet] attribute. So this method only responds to HTTP get request when editing data.
2. The "Edit" action method also receives "id" of the employee that is being edited. This "id" is used to retrieve the employee details.
3. The employee object is passed to the view

Step 2: Add "Edit" view
a) Right click on the "Edit" controller action method, and select "Add view" from the context menu
b) Set
    View name = Edit
    View engine = Razor
    Select "Create a strongly-typed view" check box
    Model class = "Employee"
    Scaffold template = "Edit"
    Finally click "Add" button
c) This should add "Edit.cshtml" to "Employee" folder in "Views" foolder
d) Delete the following scripts section that is present at the bottom of "Edit.cshtml" view
@section Scripts 
{
    @Scripts.Render("~/bundles/jqueryval")
}

Run the application and navigate to http://localhost/MVCDemo/Employee/Index. This page should list all the employees. Click on "Edit" link. The "Edit" page should display the details of the "Employee" being edited. Notice that, by default "textboxes" are used for editing. It is ideal to have a dropdownlist for gender rather than a textbox. To achieve this. make the following changes to "Edit.cshtml"

REPLACE THE FOLLOWING CODE
@Html.EditorFor(model => model.Gender)
@Html.ValidationMessageFor(model => model.Gender)

WITH
@Html.DropDownList("Gender", new List<SelectListItem>
    {
    new SelectListItem { Text = "Male", Value="Male" },
    new SelectListItem { Text = "Female", Value="Female" }
    }, "Select Gender")
@Html.ValidationMessageFor(model => model.Gender)

Run the application. Edit an employee, and notice that a DropDownList is used for gender as expected. Post the form by clicking on "Save" button. We will get an error stating - The resource cannot be found. We will discuss fixing this in our next video.