C# EF Doesn't save multiple records using ForEach

Question

Good day guys,

I'm trying to save a multiple records.

I've done my research but none of them actually works on my end.

Here's my code:

var dataToUpdate = context.Employees.ToList(); 

using(var db = context){
   var department= "IT";

   dataToUpdate.ForEach(x=>{
       x.department = department;
   });

   db.SaveChanges()
}

Source here: EF - Update multiple rows in database without using foreach loop but it doesn't work.

I tried to put breakpoints and try catch and my breakpoint goes to db.SaveChanges without error. But when I check the data from db, no changes have occurred.

It is clear that `dataToUpdate` did not come from this `db`. So it is not tracked here. Your question is far from complete. — H H, Feb 12 '19 at 07:51
A `using {}` on a copied variable? Now your code looks artificial an hard to believe. — H H, Feb 12 '19 at 07:54
If you want to modify all rows in a table execute a simple `Update Employees SET Department=@x`. ORM's are meant to work with entities, not perform batch updates. There's nothing to be gained by loading all data on the client only to send them back with a simple change — Panagiotis Kanavos, Feb 12 '19 at 07:56
I'm using EF @PanagiotisKanavos and I can't just create a query string like that. The multiple saving also happens when a user makes a changes — AppleCiderYummy, Feb 12 '19 at 07:58
@AppleCiderYummy yes you can execute raw SQL with EF. You shouldn't use an ORM at *all* for such a query. It has nothing to do with *objects*, entities or mapping to tables — Panagiotis Kanavos, Feb 12 '19 at 08:01
It has to be about `[entity-framework-6]` ___or___ `[entity-framework-core]`, it can't be about both. — H H, Feb 12 '19 at 08:01

TanvirArjel · Accepted Answer · 2019-02-12T08:22:39.083

2

Look at! you are pulling and updating data from two different contexts. Actually it should be from same context as follows:

using(var db = context)
{
  var dataToUpdate = db.Employees.ToList();

   var department= "IT";

   dataToUpdate.ForEach(x=>{
       x.department = department;
   });

   db.SaveChanges();
}

Now it should work.

edited Feb 12 '19 at 08:22

answered Feb 12 '19 at 08:10

TanvirArjel

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Typical missing semicolon after `db.SaveChanges()` :) – BytesOfMetal Feb 12 '19 at 08:15
@Petaflop Oh! Thanks. – TanvirArjel Feb 12 '19 at 08:16

C# EF Doesn't save multiple records using ForEach

1 Answers1