Adding a New Field to the Movie Model and Table (C#) | Microsoft Docs
There are two tables, one for the Movie entity set and then the EdmMetadata table. The EdmMetadata table is. To complete the tutorial, add the following Delete method to the home NET MVC 3 application with validation. Rivalries Wolverine and Ryu: Wolverine and Ryu are rivals due to the fact that increasing his knowledge in both fields in order to avenge his mother's death Both also share an opposite relation, X is a creation while Tron is a creator/ inventor. . seem to fight other characters, and not their respective rivals in MVC3 .
Add course ; db. AddModelError "", "Unable to save changes. Try again, and if the problem persists, see your system administrator. Name select d; ViewBag. Infrastructure; The PopulateDepartmentsDropDownList method gets a list of all departments sorted by name, creates a SelectList collection for a drop-down list, and passes the collection to the view in a ViewBag property.
The method accepts the optional selectedDepartment parameter that allows the calling code to specify the item that will be selected when the drop-down list is rendered. The HttpGet Create method calls the PopulateDepartmentsDropDownList method without setting the selected item, because for a new course the department is not established yet: DepartmentID ; return View course ; This code ensures that when the page is redisplayed to show the error message, whatever department was selected stays selected.
Normally the scaffolder doesn't scaffold a primary key because the key value is generated by the database and can't be changed and isn't a meaningful value to be displayed to users. For Course entities the scaffolder does include an text box for the CourseID field because it understands that the DatabaseGeneratedOption. None attribute means the user should be able enter the primary key value. But it doesn't understand that because the number is meaningful you want to see it in the other views, so you need to add it manually.
Because it's the primary key, it's displayed, but it can't be changed.
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HiddenFor helper for the course number in the Edit view. LabelFor helper doesn't eliminate the need for the hidden field because it doesn't cause the course number to be included in the posted data when the user clicks Save on the Edit page.
The Course Index page is displayed with the new course added to the list. The department name in the Index page list comes from the navigation property, showing that the relationship was established correctly.
Run the Edit page display the Course Index page and click Edit on a course. Change data on the page and click Save. The Course Index page is displayed with the updated course data.
Accessing your Model's Data from a Controller (C#)
Adding an Edit Page for Instructors When you edit an instructor record, you want to be able to update the instructor's office assignment. The Instructor entity has a one-to-zero-or-one relationship with the OfficeAssignment entity, which means you must handle the following situations: If the user clears the office assignment and it originally had a value, you must remove and delete the OfficeAssignment entity.
If the user enters an office assignment value and it originally was empty, you must create a new OfficeAssignment entity. If the user changes the value of an office assignment, you must change the value in an existing OfficeAssignment entity.
It's setting up data for a drop-down list, but you what you need is a text box. Replace this method with the following code: You can't perform eager loading with the Find method, so the Where and Single methods are used instead to select the instructor. Replace the HttpPost Edit method with the following code. The code does the following: Gets the current Instructor entity from the database using eager loading for the OfficeAssignment navigation property.
This is the same as what you did in the HttpGet Edit method. Updates the retrieved Instructor entity with values from the model binder. The TryUpdateModel overload used enables you to whitelist the properties you want to include. This prevents over-posting, as explained in the second tutorial. The Genres table contains the genre name and description.
Likewise, the Albums table doesn't contain the album artists name, but a foreign key to the Artists table. The Artists table contains the artist's name. If you examine the data in the Albums table, you can see each row contains a foreign key to the Genres table and a foreign key to the Artists table. The image below show some table data from the Albums table. For edit forms, when the current value is known, the select list can display the current value. We saw this previously when we set the selected value to Comedy.
The select list is ideal for displaying category or foreign key data. In the image below, the genre selected is Disco and the artist is Donna Summer. The SelectList constructor overload used above takes three arguments: An IEnumerable containing the items in the list. In the example above, the list of genres returned by db. The name of the property in the IEnumerable list that contains the key value.What Are Your Relationship Values
In the example above, GenreId and ArtistId. The name of the property in the IEnumerable list that contains the information to display.
In both the artists and genre table, the name field is used. DropDownList helper markup for the genre field. Empty The first line shows that the create view takes an Album model.
Accessing your Model's Data from a Controller (C#) | Microsoft Docs
In the Create method shown above, no model was passed, so the view gets a null Album model. At this point we are creating a new album so we don't have any Album data for it. DropDownList overload shown above takes the name of the field to bind to the model. It also uses this name to look for a ViewBag object containing a SelectList object. The second parameter String.
Empty is the text to display when no item is selected.
- Examining the Generated Code
- Installation Notes
- Adding a Rating Property to the Movie Model
This is exactly what we want when creating a new album. This strongly typed approach enables better compile-time checking of your code and richer IntelliSense in the Visual Web Developer editor.
fabula-fantasia.info MVC 3 | Microsoft Docs
We're using this approach with the MoviesController class and Index. Notice how the code creates a List object when it calls the View helper method in the Index action method. The code then passes this Movies list from the controller to the view: When you created the movie controller, Visual Web Developer automatically included the following model statement at the top of the Index. For example, in the Index. Among other benefits, this means that you get compile-time checking of the code and full IntelliSense support in the code editor: Working with SQL Server Compact Entity Framework Code First detected that the database connection string that was provided pointed to a Movies database that didn't exist yet, so Code First created the database automatically.
If you don't see the Movies. Then expand the Tables folder to see the tables that have been created in the database. Note If you get an error when you double-click Movies. For links to the software, see the list of prerequisites in part 1 of this tutorial series. If you install the release now, you'll have to close and re-open Visual Web Developer.
There are two tables, one for the Movie entity set and then the EdmMetadata table. The EdmMetadata table is used by the Entity Framework to determine when the model and the database are out of sync. Right-click the Movies table and select Show Table Data to see the data you created.