Question

I’m hoping I named this question right and that I can explain properly what I mean. I have a list<> of a ViewModel that has been populated from the DB and in my controller I am trying to access a specific single item of that list by one of the item’s properties values and change another property value.

For example my model might have a couple of properties:

    public int Id { get; set; }
    public bool IsChanged { get; set; }

and I want to access it by the ‘Id’ and change the ‘IsChanged’ property like so (I’m using #’s around the part I’m not sure about)

    list.#(select item in the list by it's Id)#.IsChanged = true;

I hope this makes sense and even if you may have a good link to a tutorial,
Thanks 🙂

Answer 1

If I understand correctly, using Single would lead to a null error if there are no matches, I would rather prefer using a SingleOrDefault which would return a null if there is no match… Here is probably a safe approach:

if(list != null)
{
  var item = list.SingleOrDefault(x => x.Id == 1);
  if(item !=null)
  {
    item.IsChanged = true;
  }
  else
  {
   // code to handle this case
  }
}
else
{
  // code to handle this case
}

And this is by far the best book I have read on LINQ…LINQ to Objects Using C# 4.0

Cheers…