sending db object to new thread's class

Question

i want to send db object to my new thread's constructor method how can i do

db = DBContext.CreateInstance(ConfigurationManager.ConnectionStrings["EDocSis.DAL.EDefterDB"].ConnectionString);
    FaturaUploadTreadHelper helper = new FaturaUploadTreadHelper(kurumVeriAktarimList);
                        ThreadStart job = new ThreadStart(helper.UpdateRecords);
                        Thread thread = new Thread(job);
                        thread.Start();


/////////////////////////////////////////////////////////////////
 public string ManuelFaturaUploadDirectory
        {
            get { return ConfigurationManager.AppSettings.Get("ManuelFaturaUploadDirectory"); }
        }
        public IEDefterDB db { get; set; }
        public string RealFileName { get; set; }
        public string KurumVkn { get; set; }
        public string FileExtension { get; set; }
        public int RowCount { get; set; }
        public long ContentLength { get; set; }
        public int KurumID { get; set; }
        public int VeriAktarimID { get; set; }
        public List<EDocSis.DAL.EFatura.KurumVeriAktarim> KurumVeriAktarimlariList { get; set; }

        public FaturaUploadTreadHelper(List<EDocSis.DAL.EFatura.KurumVeriAktarim> kurumVeriAktarimlariList = null)
        {

            this.KurumVeriAktarimlariList = kurumVeriAktarimlariList;
        }

        public void UpdateRecords()
        {
            foreach (var kurumVeriAktarim in this.KurumVeriAktarimlariList)
            {
                this.VeriAktarimID = kurumVeriAktarim.ID;
                var tempFileName = Path.GetFileName(kurumVeriAktarim.DosyaBilgisi);
                this.RealFileName = tempFileName;
                var vkn = db.KurumDetaylari.First(x => x.ID == kurumVeriAktarim.Parent.ID).KimlikNo;
                this.KurumVkn = vkn;
                var extension = Path.GetExtension(kurumVeriAktarim.DosyaBilgisi);
                this.FileExtension = extension;
                this.RowCount = kurumVeriAktarim.SatirSayisi;
                this.ContentLength = kurumVeriAktarim.ToplamBuyukluk;
                this.KurumID = kurumVeriAktarim.Parent.ID;
                Run();
            }

Each thread should have their own DB instance. Why don't you passes the connection string, instead? — EProgrammerNotFound, Dec 03 '13 at 14:20
so i should create db object in constructor method for each thread is it true ? — altandogan, Dec 03 '13 at 14:21
As @Michael said, we can't dictate anything since we don't know if `DBContext` is thread safe. Usually, they don't, but who knows? — EProgrammerNotFound, Dec 03 '13 at 14:25
If you are using ADO.Net and multithread, so no, it's not thread safe and in this case you should use one DB for each thread — EProgrammerNotFound, Dec 03 '13 at 14:28
Please, read [this](http://stackoverflow.com/questions/9099359/entity-framework-and-multi-threading) and [this](http://stackoverflow.com/questions/9415955/c-sharp-working-with-entity-framework-in-a-multi-threaded-server) and finally [this](http://stackoverflow.com/questions/7176303/entity-framework-multiple-threads-lazy-load) — EProgrammerNotFound, Dec 03 '13 at 14:34

Mike Perrenoud · Answer 1 · 2013-12-03T14:44:17.420

3

The Thread.Start method has an overload that receives an object. Modify your method UpdateRecords to receive an object:

UpdateRecords(object db)

then change this line ThreadStart job = new ThreadStart(helper.UpdateRecords); to this:

ParameterizedThreadStart job =
    new ParameterizedThreadStart(helper.UpdateRecords);

and then when you start the thread:

thread.Start(db);

As stated by Matheus, it's likely that each thread should have its own db instance, but I can't really dictate that. I don't know near enough (and honestly couldn't) about your application.

edited Dec 03 '13 at 14:44

answered Dec 03 '13 at 14:21

Mike Perrenoud

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i don't TreadStart methods want to any void method when i give a parameter objec db it don't accept it understand ThreadStart job = new ThreadStart(helper.UpdateRecords); Thread thread = new Thread(job); thread.Start(db); – altandogan Dec 03 '13 at 14:35
@user990513, I'm not understanding what you're saying. The method that you're starting on a new thread, `UpdateRecords`, can be modified to receive the `db` object. It just needs to have a parameter typed as an `object`. You'd clearly have to cast it inside of there. Then, when you issue `Thread.Start`, just pass that object into it. – Mike Perrenoud Dec 03 '13 at 14:41
2

@user990513 OP needs to change ThreadStart to [ParametrizedThreadStart](http://msdn.microsoft.com/en-us/library/system.threading.parameterizedthreadstart(v=vs.110).aspx) – EProgrammerNotFound Dec 03 '13 at 14:42
@MatheusFreitas, fantastic addition my friend! Just fantastic. I'll update the answer. – Mike Perrenoud Dec 03 '13 at 14:43

Bura Chuhadar · Accepted Answer · 2013-12-03T22:25:00.997

You can do it like that:

db = DBContext.CreateInstance(ConfigurationManager.ConnectionStrings["EDocSis.DAL.EDefterDB"].ConnectionString);
    FaturaUploadTreadHelper helper = new FaturaUploadTreadHelper(kurumVeriAktarimList);

                        Thread thread = new Thread(
                            unused => UpdateRecords(db)
                        );
                        thread.Start();

        public void UpdateRecords(object db)
        {
//DBContext for thread safe purposes.
 db = DBContext.CreateInstance(ConfigurationManager.ConnectionStrings["EDocSis.DAL.EDefterDB"].ConnectionString);

            foreach (var kurumVeriAktarim in this.KurumVeriAktarimlariList)
            {
                this.VeriAktarimID = kurumVeriAktarim.ID;
                var tempFileName = Path.GetFileName(kurumVeriAktarim.DosyaBilgisi);
                this.RealFileName = tempFileName;
                var vkn = db.KurumDetaylari.First(x => x.ID == kurumVeriAktarim.Parent.ID).KimlikNo;
                this.KurumVkn = vkn;
                var extension = Path.GetExtension(kurumVeriAktarim.DosyaBilgisi);
                this.FileExtension = extension;
                this.RowCount = kurumVeriAktarim.SatirSayisi;
                this.ContentLength = kurumVeriAktarim.ToplamBuyukluk;
                this.KurumID = kurumVeriAktarim.Parent.ID;
                Run();
            }

One thing you must know that, DBContext is not thread safe, even you send your object as a parameter, you have to create a new connection. But also it doesn't make sense to send your dbContext as a parameter for your method.

i am doing this but i receive that error :The ObjectContext instance has been disposed and can no longer be used for operations that require a connection. var vkn = db.KurumDetaylari.First(x => x.ID == kurumVeriAktarim.Parent.ID).KimlikNo; — altandogan, Dec 03 '13 at 14:55
One thing you must know that, DBContext is not thread safe, even you send your object a parameter, you have create a new connection. But also it doesn't make sense to send your dbContext as a parameter for your method. — Bura Chuhadar, Dec 03 '13 at 15:05
sending dbContext is a bad approach ? is it True? if is it true i will create a db connection in my thread method — altandogan, Dec 03 '13 at 15:08
if you are using threads then yes it is a bad approach to send the dbContext as a parameter. — Bura Chuhadar, Dec 03 '13 at 15:15

sending db object to new thread's class

2 Answers2