C#

Adriaan Davel wrote:

After much painfull and brain numbing reading I still don't understand why its not possible to cast between Action<T> and Action<object>,

I are Troll

Adriaan Davel wrote:

this object x = 1; works

I are Troll

private void Button_Click(object sender, RoutedEventArgs e)
{
    Calc(1);
}

private void Calc(object val)
{

}

Eddy Vluggen wrote:

but that doesn't make 'em interchangeable

J4amieC wrote:

Yes it does, assuming the container being used to intercahnge them types the variable as object.

I are Troll

Eddy Vluggen wrote:

Once you state that everything is an object, people will assume that anything can be used as a base to derive from

J4amieC wrote:

Any non-sealed Type can be used as a base to derive from.

J4amieC wrote:

What's your point?

I are Troll

Action<object> act = null;
act = new Action<int>();

act("a");

public interface IBase<T>
{
    Func<T> OnComplete { get; set; }
}

public class Base : IBase<object>
{
        
    public Base(Func<object> onComplete)
    {
        OnComplete = onComplete;
    }

    public Func<object> OnComplete { get; set; }
}
public class GenericBase<T> : IBase<T>
{
    public GenericBase(Func<T> onComplete)
    {
        OnComplete = onComplete;
    }

    public Func<T> OnComplete { get; set; }
}

class BadMistake {
  void CompleteHandler(Dictionary<string,int> complexParameter){
    // some stuff
  }
  
  GenericBase<Dictionary<string,int>> instance;

  public void CauseDeath(){
    instance = new GenericBase<Dictionary<string,int>>(CompleteHandler);
    ((Base)instance).OnComplete(16);
  }
}

public class Base
{
   public Func<T> OnComplete {get;set;} where T:Panel
   public Base(Func<T> onComplete) where T:Panel
   {
      OnComplete = onComplete;
   }
}
public class GenericBase<T> : Base
{
   public GenericBase(Func<T> onComplete) where T:UserControl : base(onComplete)
   {
      OnComplete = onComplete;
   }
}

Rob Philpott wrote:

Covariance and Contravariance