'Delete query in Linq

I have this simple code but it shows error. I dont know where I am going wrong. It shows error in last line.

 linq_testDataContext db = new linq_testDataContext();
 var remove = from aremove in db.logins
         where aremove.username == userNameString && aremove.Password == pwdString
         select aremove;
 db.logins.DeleteOnSubmit(remove);
c++sharplinqlinq-to-sql


Solution 1:[1]

DeleteOnSubmit takes a single object. You are passing an IEnumerable<login> to it. Use DeleteAllOnSubmit instead, or select a single object from your resulting collection, like this:

var remove = (from aremove in db.logins 
             where aremove.username == userNameString 
                && aremove.Password == pwdString 
             select aremove).FirstOrDefault(); 

if(remove != null)
{
    db.logins.DeleteOnSubmit(remove);
}

Solution 2:[2]

you are missing foreach loop to delete all entity.

Use like below

var remove = from aremove in db.logins
     where aremove.username == userNameString && aremove.Password == pwdString
     select aremove;

and after that

foreach (var detail in remove)
{
    db.logins.DeleteOnSubmit(detail);
}

and at last 

 try
{
    db.SubmitChanges();
}
catch (Exception e)
{
    // Provide for exceptions.
}

Hope this will help you.

Solution 3:[3]

Instead of:

db.logins.DeleteOnSubmit(remove);

Call DeleteAllOnSubmit(), like this:

db.logins.DeleteAllOnSubmit(remove.ToList());

Make sure to call db.SubmitChanges() afterwards. You could use .AsEnumerable() as well, either or. If it's a large delete operation though, you may want to think about bypassing LINQ in this case.

Solution 4:[4]

use this code its work

var remove = (from aremove in db.logins 
             where aremove.username == userNameString 
                && aremove.Password == pwdString 
             select aremove).FirstOrDefault(); 

if(remove != null)
{
     db.logins.Remove(remove);
     db.SaveChanges();
}

Solution 5:[5]

try using the method first(), something like this:

var remove = 
    (from aremove in db.logins where aremove.username == userNameString 
    && aremove.Password == pwdString select aremove).first();

db.logins.DeleteOnSubmit(remove);

Solution 6:[6]

For good practices

 private void DeleteCourse()
        {
            int id = Convert.ToInt32( txtSearch.Text);
            CourseDemoDataContext cdContext = new CourseDemoDataContext();
            course courseobj = cdContext.courses.Single(courses => courses.COURSE_ID == id);
            cdContext.courses.DeleteOnSubmit(courseobj);
            cdContext.SubmitChanges();
        }

Solution 7:[7]

You can try this, It will be worked for you.

linq_testDataContext _DbContext = new linq_testDataContext();
var remove = _DbContext.aremove.where(x=>x.username == userNameString && x.Password == pwdString).FirstOrDefault();
if(remove != null)
{
     db.logins.Remove(remove);
     db.SaveChanges();
}

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Philip Daubmeier
Solution 2 Mukesh Kumar
Solution 3 Nick Craver
Solution 4 shebin c babu
Solution 5 skamlet
Solution 6 sarder kamruzzaman polash
Solution 7 Qais Ali Abbas

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