Updating database entry MVC Entity Framework

Question

I have a Payment model with a 'Status' boolean value which defaults to false. Once payment has been made, I need to update that specific payment's 'Status' to true.

Here's the code I've been trying to use to change the specific database entry, but it's just not changing it. What am I doing wrong?

Payment payment = new Payment();
payment = db.Payments.Find(orderId);
db.Entry(payment).State = EntityState.Modified;
payment.Status = true;
db.SaveChanges();

Thanks!

This is what ended up working:

using (var con = new ApplicationDbContext())
{
    payment = con.Payments.First(x => x.Id == orderId);
    payment.Status = true;

    con.Payments.Attach(payment);
    var entry = con.Entry(payment);
    entry.Property(e => e.Status).IsModified = true;
    con.SaveChanges();
}

Answer 1

Payment payment = new Payment();
payment = db.Payments.Find(orderId);
payment.Status = true;
db.Entry(payment).State = EntityState.Modified;
db.SaveChanges();

Answer 2

The reason all of these are failing is because either the Payment object is never attached to the DBContext or the orderId doesn't actually match up with the PK on the Payments table. In order for SaveChanges() to actually work, the object you're changing needs to be tracked by the DBContext, not just have its EntityState set to Modified. Also all these examples seem grossly overcomplicated.

using (var db = new DbContext())
{
    // make sure you have the right column/variable used here
    var payment = db.Payments.FirstOrDefault(x => x.Id == orderId);

    if(payment == null) throw new Exception("Invalid id: " + orderId);

    // this variable is tracked by the db context
    payment.Status = true;

    db.SaveChanges();
}

Answer 3

If you just have your entity id, just do like Ali Golshani said. But if you already have the entity and just want to update, you can do this way:

 public void Update(Payment payment, int orderId)
    {
        //first find the entity to update
        Payment oldEntity = DbSet.Find(orderId);

        //detach this entity from the DbSet
        Db.Entry(oldEntity).State = EntityState.Detached;

        //set the state from the entity that you just received to modified 
        Db.Entry(obj).State = EntityState.Modified;
    }

Detaching avoids the error message: "Attaching an entity failed because another entity of the same type already has the same primary key value".

I hope that it helps.

Answer 4

Try this one:

    Payment payment;
    using (var context = new DBContext()) //replace the name of your context
    {
        payment = context.Payments.Find(orderId);
    }

    if(payment != null)
    {
       payment.Status = true;
    }

    using (var context = new DBContext()) //replace the name of your context
    {
        context.Payments.Attach(payment);
        context.Entry(payment).State = System.Data.EntityState.Modified;    
        context.SaveChanges();
    }

Answer 5

As mentioned here:

The Find method on DbSet uses the primary key value to attempt to find an entity tracked by the context. If the entity is not found in the context then a query will be sent to the database to find the entity there. Null is returned if the entity is not found in the context or in the database.

So be sure that Payment class looks like this:

public class Payment
{
     [Key]
     public int Id {get; set;}
     public bool Status {get; set;}
}

And your Entry save logic could look like this:

Payment payment = null;
using (var ts = new TransactionScope(TransactionScopeOption.Required, new TimeSpan(1, 0, 0, 0)))
{
    using (var context = new DBContext()) 
    {
        context.Database.Log = s => { System.Diagnostics.Debug.WriteLine(s); };
        payment = context.Payments.Find(orderId);
        if(payment != null)
        {
            payment.Status = true;
            context.Entry(payment).State = System.Data.EntityState.Modified;    
        }
        else 
        {
            context.Payments.Add(new Payment(){
                Status = true
            });
        }
        context.SaveChanges();
    }
    ts.Complete();
}

Added transaction scope to be sure that it is properly open and close, and added sql query logging to debug window.