Question

Problem Description:
I am using ASP.NET MVC and I have the following method in my Controller Class. This method uses SelectList method to select a list of items from the database. These items will then be passed to the view to be displayed in a drop down list.

public ActionResult Edit(int id)
{
    Album album = db.Albums.Find(id);

    ViewBag.ArtistId = new SelectList(db.Artists, "ArtistId", "Name", album.ArtistId);
    return View(album);
}

My Understanding of the selectMethod:

I know that the first param takes a list of items.
The third param is the property to be displayed.In this case, we will be displaying the name property of the Artists.
Based on my research, I found out that the 4th param is the default value that will be displayed on the dropdown list.

My Question:

1) I would like someone to help me understand about the second param.

2)Since we are displaying names of the artists, how can we display a default artist name in the fourth param using Artist ID?

I hope you guys understood my questions. I would be happy to clarify them to you if you need me to do so.

Answer 1

1. The second parameter is the name of the “value” property or field on each element in the first parameter. Since two artists could conceivably have the same, it’s generally better to use an ID column (as in the example) so that you know specifically which item was selected.
2. In the example, you are providing the artist of the currently-viewed album as the default to appear. Assuming that db.Artists includes an artist whose ArtistId property matches the given value, the rendered HTML will produce a select list where that artist is selected.

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