C# Passing generic class as an event parameter

Question

I\'ve been working with generics over the last few days and I encountered an issue by trying to pass generic types as parameters in events/delegates.

A very friendly me

Answer 1

ou can make Catalog class generic. That will allow you to use GenericListItemCountChangedEvent T

public class Catalog where T: BaseItem
{
    public delegate void GenericListItemCountChangedEvent(object sender, GenericListItemCountChangedEventArgs e) where T : BaseItem;
    //This is the point where it does not work, because I specify BaseItem as the type
    public event EventHandler> GenericListItemCountChanged;

    private void RaiseGenericListItemCountChangedEvent(List List)
    {
        if (GenericListItemCountChanged != null)
        {
            GenericListItemCountChanged(this, new GenericListItemCountChangedEventArgs(List));
        }
    }

    public class GenericListItemCountChangedEventArgs : EventArgs where T : BaseItem
    {
        private List _changedList_propStore;
        public List ChangedList
        {
            get
            {
                return _changedList_propStore;
            }
        }

        public GenericListItemCountChangedEventArgs(List ChangedList)
        {
            _changedList_propStore = ChangedList;
        }
    }
}

public  class MainWindow 
{
    public MainWindow()
    {
        new Catalog().GenericListItemCountChanged += (sender, e) => GenericListItemCountChanged(sender, e);
    }

    private void GenericListItemCountChanged(object sender, Catalog.GenericListItemCountChangedEventArgs e) where T : BaseItem
    {
        //Use Generic EventArgs
    }
}