如何在MVC中使用where子句ef

Question

Using MVC EF, how would I filter results by a field other than the id?

return View(db.Drafts.Where(PublicationId=id));

PublicationId is a column in the Drafts table.

Any help is appreciated.

Answer 1

public ActionResult Index(int id)
{
    var drafts = db.Drafts.Where(d => d.PublicationId == id).ToList();
    return View(drafts);
}

or if you wanna single draft (coz the id is usually unique):

public ActionResult Index(int id)
{
    var draft = db.Drafts.SingleOrDefault(d => d.PublicationId == id);
    return View(draft);
}

Answer 2

I'm not sure what your Draft class looks like, but let's pretend it looks something like this:

public class Draft
{
    public int Id { get; set; }
    public int PublicationId { get; set; }
    public string Name { get; set; }
}

You could write a query like this:

return View(db.Drafts.Where(d => d.Name == "foo"));

This would only return Drafts that had a name of "foo". This by itself probably isn't useful. You would more than likely want to control this by passing data into your controller (query string, form value, route value, etc.):

public ActionResult Index(int id, string filter)
{
    return View(db.Drafts.Where(d => d.Name == filter));
}

Or you could filter on multiple properties:

public ActionResult Index(int id, string filter)
{
    return View(db.Drafts.Where(d => d.Name == filter && d.PublicationId == id));
}

Answer 3

Are you familiar with lambdas? In the lambda of your where clause, you can specify any property you want to.

return View(db.Drafts.Where(d => d.SomeProperty == value));

I would also consider putting the data your delivering to the page in a model, rather than making the model be the actual POCO model. An MVC model drives the display, a POCO model drives your data.