The property 'Id' is part of the object's key information and cannot be modified. multirow

Question

I get the following error when I add more than one row: The property 'Id' is part of the object's key information and cannot be modified. multirow

if (tblCari.TblCariAdres.Count != 0) {
    TblCariAdres tblCariAdres = new TblCariAdres();
    foreach (var item in tblCari.TblCariAdres) {
        tblCariAdres.Id = Guid.NewGuid();
        tblCariAdres.FirmaId = tblCari1.FirmaId;
        tblCariAdres.CariId = tblCari1.Id;
        tblCariAdres.Tanim = item.Tanim;
        tblCariAdres.Isim = item.Isim;
        tblCariAdres.Adres = item.Adres;
        tblCariAdres.Ilce = item.Ilce;
        tblCariAdres.Sehir = item.Sehir;
        tblCariAdres.Telefon = item.Telefon;
        tblCariAdres.Aciklama = item.Aciklama;

        Db.TblCariAdres.Add(tblCariAdres);
        Db.SaveChanges();
    }
}

Answer 1

You are trying to add the same variable to the database multiple times. As such your database submission (Db.SaveChanges()) is trying to change the Id (and other properties) of the existing entity on the second loop.

Try moving this line into the loop: TblCariAdres tblCariAdres = new TblCariAdres();

Such that your code looks like the below:

if (tblCari.TblCariAdres.Count != 0) {
    foreach (var item in tblCari.TblCariAdres) {
        TblCariAdres tblCariAdres = new TblCariAdres();
        
        tblCariAdres.Id = Guid.NewGuid();
        tblCariAdres.FirmaId = tblCari1.FirmaId;
        tblCariAdres.CariId = tblCari1.Id;
        tblCariAdres.Tanim = item.Tanim;
        tblCariAdres.Isim = item.Isim;
        tblCariAdres.Adres = item.Adres;
        tblCariAdres.Ilce = item.Ilce;
        tblCariAdres.Sehir = item.Sehir;
        tblCariAdres.Telefon = item.Telefon;
        tblCariAdres.Aciklama = item.Aciklama;

        Db.TblCariAdres.Add(tblCariAdres);
        Db.SaveChanges();
    }
}