How can I delete multiple rows with Entity Framework?

Question

I have this code but it doesn't work :

public bool DeleteAccess(int _UserID, IEnumerable<int> _ModulID)
{
    MPortalContext db=new MPortalContext();
    foreach (var item in _ModulID)
    {
        var validation = db.WebSite_PermissionDB.Where(x => x.UserID == _UserID && x.ModuleID == item);
        db.WebSite_PermissionDB.Remove(validation);
    }
    db.SaveChanges();
    return true;
}

my (_ModulID) is a collection of ids that i filter them and then with foreach delete them but it doesn't work ??

Subhash Rao · Accepted Answer · 2014-03-27 12:40:08Z

2

one way to delete is

context.Database.SqlQuery<WebSite_PermissionDB>(
  "DELETE FROM Users WHERE UserID = @userId  ",
  new [] { new SqlParameter("@userId ", 1) }
);

answered Mar 27, 2014 at 12:40

Subhash Rao

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Comments

Selman Genç · Accepted Answer · 2014-03-27 12:35:07Z

1

First get the all entities that mathces with your condition, then use RemoveRange method:

var entities = db.WebSite_PermissionDB
           .Where(x => x.UserID == _UserID && _ModulID.Contains(x.ModuleID));

db.WebSite_PermissionDB.RemoveRange(entities);

db.SaveChanges();

Also you might want to use using statement in order to make sure that your DbContext is Disposed properly.

using(MPortalContext db = new MPortalContext())
{ 
     ...
}

answered Mar 27, 2014 at 12:35

Selman Genç

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1 Comment

A.A Over a year ago

In my code : dont know RemoveRange & Contains . But i use nameSpaces :using System.Data.Entity; & using System.Data.Objects.DataClasses; ??but dont know.

Meysam Khoshbakht · Accepted Answer · 2014-03-27 12:38:19Z

0

var distinctResult = db.WebSite_PermissionDB.Distinct();
db.WebSite_PermissionDB.RemoveRange(db.WebSite_PermissionDB.Except(distinctResult));
db.SaveChanges();

answered Mar 27, 2014 at 12:38

Meysam Khoshbakht

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2 Comments

Dutts Over a year ago

Could you add some explanation for what this code sample does to your answer?

Meysam Khoshbakht Over a year ago

first select data by removing duplicate rows(Distinct method), then remove all rows unless selected data (Except method) in previous code.

A.A · Accepted Answer · 2014-03-27 13:03:00Z

0

    MPortalContext db=new MPortalContext();
    foreach (var item in _ModulID)
    {
        var validation = db.WebSite_PermissionDB.Where(x => x.UserID == _UserID && x.ModuleID == item).FirstOrDefault();
        db.WebSite_PermissionDB.Remove(validation);
        db.SaveChanges();
    }  
    return true;

I forget use .FirstOrDefault(); now correct. Thank friends.

answered Mar 27, 2014 at 13:03

A.A

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