C#•11mo ago

dbContext.Remove removes from application, but in database it remains

I click the delete button, it gets removed from the program. I check in sqlite db browser and the record is still there? This persists through rebuilds and reruns, in the program it doesn't show, in the db browser it does. This is a WinForms project btw

68 Replies

Angius•11mo ago

$code

MODiX•11mo ago

To post C# code type the following: ```cs // code here ``` Get an example by typing $codegif in chat For longer snippets, use: https://paste.mod.gg/

null•11mo ago

Did you call .dbContext.SaveChanges() after the remove?

Jimmacle•11mo ago

this also sounds like you're using the same dbcontext for a long time, which is not how you should be using it

\AliOP•11mo ago

yes

private void dgvUvjerenja_CellClick(object sender, DataGridViewCellEventArgs e)
{
    if (e.ColumnIndex == 5)
    {
        DialogResult dr = MessageBox.Show("Da li zelite izbrisati ovo uvjerenje?", "", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
        if (dr == DialogResult.Yes)
        {
            var selectedItem = dgvUvjerenja.SelectedRows[0].DataBoundItem as StudentUvjerenjeIB220319;
            dbContext.StudentiUvjerenjaIB220319.Remove(selectedItem);
            dbContext.SaveChanges();

            UcitajUvjerenja();
        }
    }
}

private void dgvUvjerenja_CellClick(object sender, DataGridViewCellEventArgs e)
{
    if (e.ColumnIndex == 5)
    {
        DialogResult dr = MessageBox.Show("Da li zelite izbrisati ovo uvjerenje?", "", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
        if (dr == DialogResult.Yes)
        {
            var selectedItem = dgvUvjerenja.SelectedRows[0].DataBoundItem as StudentUvjerenjeIB220319;
            dbContext.StudentiUvjerenjaIB220319.Remove(selectedItem);
            dbContext.SaveChanges();

            UcitajUvjerenja();
        }
    }
}

\AliOP•11mo ago

\AliOP•11mo ago

It gets removed from my program, but in the db browser even after I refresh and restart the program it doesnt want to go away somehow

Jimmacle•11mo ago

does it show up again in your program when you restart it?

\AliOP•11mo ago

Jimmacle•11mo ago

then you're looking at 2 different databases

\AliOP•11mo ago

I only have one database

Jimmacle•11mo ago

humor me and make sure that you're opening the exact same file your program is

\AliOP•11mo ago

If I add a record manually, it shows up correctly for example I add a record in the db and open the corresponding Student, it will show me the entry, so its the right database?

Jimmacle•11mo ago

without any restarts/rebuilds?

\AliOP•11mo ago

yes actually nvm it doesnt live update even tho i run a query on each time the new form is opened more info: I added a new record to that table, and on rerunning my program, it shows the record i deleted previously

Jimmacle•11mo ago

does it also show the new record?

\AliOP•11mo ago

after I rerun the program, it shows the new record I added and the old one which was hidden when I clicked delete so 2 records, and 2 in the database

Jimmacle•11mo ago

where is dbContext coming from?

\AliOP•11mo ago

I have a project which is ProjectName.Core and ProjectName.WinForms, and the db is in the root folder of ProjectName.WinForms, I dont know if that should be interferring

Jimmacle•11mo ago

i'm going to guess this is an issue with either a long-lived dbcontext, trying to use untracked entities, or both

\AliOP•11mo ago

because this is part of an exam task and the way the files are strucutred including the database is something I cant change you mean where is it defined or?

Jimmacle•11mo ago

yes and when is it created and disposed

\AliOP•11mo ago

its defined in ProjectName.Core, but I made a new instance in the form Im opening its a private field

Jimmacle•11mo ago

you should make a new instance for every operation

\AliOP•11mo ago

What

Jimmacle•11mo ago

they aren't designed to stick around for a long time so for example here, you should be creating a new dbcontext in your event handler and disposing it

\AliOP•11mo ago

I watched lectures from my uni professors and they add a field, and then use that

Jimmacle•11mo ago

then they're wrong

\AliOP•11mo ago

lemme try

Jimmacle•11mo ago

it can work but it's not how it was designed to be used and can cause desynchronization and change tracking issues maybe i'm jaded, but always take your school's examples and "best practices" with a grain of salt they're usually not the best

\AliOP•11mo ago

Ive made it like this

var dbContext = new DLWMSDbContext();
var selectedItem = dgvUvjerenja.SelectedRows[0].DataBoundItem as StudentUvjerenjeIB220319;
dbContext.StudentiUvjerenjaIB220319.Remove(selectedItem);
dbContext.SaveChanges();

UcitajUvjerenja();

var dbContext = new DLWMSDbContext();
var selectedItem = dgvUvjerenja.SelectedRows[0].DataBoundItem as StudentUvjerenjeIB220319;
dbContext.StudentiUvjerenjaIB220319.Remove(selectedItem);
dbContext.SaveChanges();

UcitajUvjerenja();

and it still isnt working

Jimmacle•11mo ago

you shouldn't use the class that's in your data grid or whatever that is, you need to get it from the database again by ID or just ExecuteDelete it the only entities that you should ever pass into a dbcontext should be entities returned by a query to that dbcontext (or brand new ones that you're adding) also, you need to put the dbcontext in a using so it's disposed correctly

\AliOP•11mo ago

thats what I did before and it still didnt work, so I looked at the solution and the guy did this

var selectedItem = dgvUvjerenja.SelectedRows[0].DataBoundItem as StudentUvjerenjeIB220319;
dbContext.Remove(dbContext.StudentiUvjerenjaIB220319.Single(item => item.Id == selectedItem.Id));
dbContext.SaveChanges();

var selectedItem = dgvUvjerenja.SelectedRows[0].DataBoundItem as StudentUvjerenjeIB220319;
dbContext.Remove(dbContext.StudentiUvjerenjaIB220319.Single(item => item.Id == selectedItem.Id));
dbContext.SaveChanges();

is this what you mean the only way I can get the item is by getting its id from the selected row

Jimmacle•11mo ago

yes, either that or ExecuteDelete to avoid making 2 queries which you don't have to do SaveChanges after because it happens immediately

Angius•11mo ago

.Execute methods my beloved pepelove

\AliOP•11mo ago

I dont have ExecuteDeleted available as a method like this dbContext.ExecuteDelete

Angius•11mo ago

Seeing how it's a school project, it probably requires an ancient version of .NET Framework, so no surprise there

\AliOP•11mo ago

its on .net 8 but winforms im running latest version

Angius•11mo ago

EF Core 8 absolutely does have .Execute methods You sure EF version is not outdated maybe?

\AliOP•11mo ago

Jimmacle•11mo ago

it's on the set, not the context

\AliOP•11mo ago

its using 7.0.1 for ef

Jimmacle•11mo ago

actually it's not even that, it's on a query

Jimmacle•11mo ago

https://learn.microsoft.com/en-us/ef/core/saving/execute-insert-update-delete

ExecuteUpdate and ExecuteDelete - EF Core

Using ExecuteUpdate and ExecuteDelete to save changes with Entity Framework Core

\AliOP•11mo ago

alr modified it let me try now it still deletes them in the program but they remain in the database until I add another record, then they all show dbContext.StudentiUvjerenjaIB220319.Where(item => item.Id == selectedItem.Id).ExecuteDelete(); I did it like this, it's correct right?

null•11mo ago

Did you dispose of the dbContext like mentioned here?

\AliOP•11mo ago

i added that part now and it still does the same bug

\AliOP•11mo ago

is this disposing properly? i suppose if its in using it implements IDisposable

Angius•11mo ago

No need to save changes after execute methods

\AliOP•11mo ago

removed it, but it had no effect anyway

Jimmacle•11mo ago

it wouldn't, it's just unnecessary

\AliOP•11mo ago

i guess my database is just cursed somehow I guess I will close the post because I cant fix it

Jimmacle•11mo ago

or leave it open to see if other people have ideas? kinda running out though, this isn't a complicated query so i doubt it's the problem

\AliOP•11mo ago

i just checked I tried changing the state of the checkbox and i did the Entry modified state thing and saved changes in the app it keeps saying that I clicked the buttona and its persistent through different runs but on the database it wasnt affected so this isnt an issue around the query at all, something is wrong with the database but we get this on an exam, I dont know how is it wrongly configured

Jimmacle•11mo ago

okay, if it's persistent through different runs then where do you think it's being persisted if not the database? i'm like 90% sure this is a problem with the db viewer you're using at this point

\AliOP•11mo ago

thats the problem, I dont know where is it persistent, and the funny thing is when I add a new record through the db viewer, and rerun my program, it removes the changes (clicking on the checkbox for example, or brings back "deleted" items)

Jimmacle•11mo ago

then it's 100% the problem

\AliOP•11mo ago

this is the db viewer https://sqlitebrowser.org/

DB Browser for SQLite

Jimmacle•11mo ago

stop using it, just use your application and see if there is still a problem

\AliOP•11mo ago

i must be doing something wrong, because in my lectures the professor used it without issues and it updated in real time with the changes in the program

Jimmacle•11mo ago

then it's an option in the program or he was doing something differently

\AliOP•11mo ago

ive downloaded this project from github, and my winforms is .net8 while my core project library has .net6 with EF version 7.0.1 instead of 8.0.1 with .net8 im gonna try updating to the latest and changing the project settings to net8 and see if it works

Jimmacle•11mo ago

sure, but i'm pretty confident it's some concurrency/multi-access issue with your other database client

\AliOP•11mo ago

Fixed it It was none of the above @jIMMACLE, I was looking in the DB browser on the file ./file.db instead of bin/Debug/file.db couldve figured this out sooner, because the app and the database were not in sync i guess I learned the hard way

Jimmacle•11mo ago

remember when i said this? https://discord.com/channels/143867839282020352/1194376684607119391/1194378791368282243

MODiX•11mo ago

Jimmacle

then you're looking at 2 different databases

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Jimmacle•11mo ago

😛

\AliOP•11mo ago

yeah but at that time i was hotheaded i didnt realize it was being copied over to debug in the exam template for the db its set to copy whenever a change has been made shouldve looked at that sooner

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dbContext.Remove removes from application, but in database it remains