Put Route Successful But Not Updating C#

March 28, 2023

Refactoring some C# code and I am trying to create a new update method. It is working successfully but its not actually updating. This is my first time doing this in C# so I have been working off a few blogs and I can’t tell whats different from what I saw on there. Here are the 2 solutions I tried:

public async Task<BillableDto> PutBillable(Guid Id, BillableDto billable)
{
    var view = await _context.Billables
                             .Where(b => b.Id == Id)
                             .SingleOrDefaultAsync();

    if (view == null) 
        throw new NotFoundException("BillableNotFound");
    
    view.Id = billable.Id;
    view.Name = billable.Name;
    view.Cost = billable.Cost;
    view.Type = billable.Type;
    view.PunchId = billable.PunchId;
    view.Punches = billable.Punches;

    _context.Update(view);

    return new BillableDto
        {
            Id = view.Id,
            Name = view.Name,
            Cost = view.Cost,
            Type = view.Type,
            PunchId = view.PunchId,
            Punches = view.Punches
        };
}

Attempt #2:

public async Task<bool> PutBillable(Guid Id, BillableDto billable)
{
    var view = await _context.Billables
                             .Where(b => b.Id == Id)
                             .SingleOrDefaultAsync();

    if (view == null) 
        throw new NotFoundException("BillableNotFound");
    
    view.Id = billable.Id;
    view.Name = billable.Name;
    view.Cost = billable.Cost;
    view.Type = billable.Type;
    view.PunchId = billable.PunchId;
    view.Punches = billable.Punches;

    _context.Update(view);

    return true 
}

Any tips on these here?

>Solution :

Not entirely clear what database and database access layer you’re using – assuming it’s some kind of Entity Framework – then you’re most likely misunderstanding the Update method on the context.

Here’s what the official MS docs says:

Begins tracking the given entity and entries reachable from the given entity using the Modified state by default, but see below for cases when a different state will be used.

Most importantly: it does NOT actually apply any update back to the database – for that, you’d need to call

await _context.SaveChangesAsync();

Also: since you’re loading the view from the context, and then making changes to it – you don’t even need to call .Update at all… the view will already be marked as "Modified" by the EF change tracker.

So try something like this:

public async Task<bool> PutBillable(Guid Id, BillableDto billable)
{
    var view = await _context.Billables
                             .Where(b => b.Id == Id)
                             .SingleOrDefaultAsync();

    if (view == null) 
        throw new NotFoundException("BillableNotFound");
    
    view.Id = billable.Id;
    view.Name = billable.Name;
    view.Cost = billable.Cost;
    view.Type = billable.Type;
    view.PunchId = billable.PunchId;
    view.Punches = billable.Punches;

    await _context.SaveChangesAsync();

    return true;
}