Question

I need to create a custom collection that implements IBindingList in order to be able to bind it with a custom control from 3rd party. Another problem that I have is that I have to make that collection thread safe because I manually insert items from multiple threads simultaneously.

Anyways I am using a BindingList<T> as a field on my class in order to don’t reinvent the wheel to much. So my class looks like:

class ThreadSaveBindingCollection<T> : IEnumerable<T>, IBindingList
{
    BindingList<T> collection;
    object _lock = new object();

    // constructors
    public ThreadSaveBindingCollection(IEnumerable<T> initialCollection)
    {
        if (initialCollection == null)
            collection = new BindingList<T>();
        else                            
            collection = new BindingList<T>(new List<T>(initialCollection));                                 
    }
    public ThreadSaveBindingCollection() : this(null)
    {            
    }   

    // Todo: Implement interfaces using collection to do the work    
}

Note I am missing to implement the interface IEnumerable and IBinding list. I am planning for the field collection to take care of that as it implements those interfaces as well. So I let visual studio implement the interface explicitly and replace the throw new NotImplementedException() with the field collection implementation and I end up with something like:

Now the question is

Why I cannot call the method AddIndex on the field collection if collection claims to implement IBindingList!?

I am not able to do the same thing for several of the methods

Answer 1

It’s because it’s an explicit implementation of the interface, rather than implicit. This means you must call it through the interface rather than the type itself. For example:

((IBindingList)collection).AddIndex(property);

See here for more information on explicit interface implementations.