Delegate Events

[deven_a76]

Hello friends,

I am new to C# and try to learn the basics. I am getting error "error CS0052: Inconsistent accessibility: field the 'Model.Notifier' is less accessible than field 'Model.notifyViews'"

Could you please let me know the error I am getting...

using System;
using System.Data;
class Model 
{
	delegate void Notifier(string sender);
	public event Notifier notifyViews;
	public void Change() 
	{
		notifyViews("Model");
	}
}

class View1
{
	public View1(Model m)
	{
		 m.notifyViews += new Notifier(this.Update1);
	}
	
	void Update1(string sender)
	{
		Console.WriteLine(sender + " was changed");
	}
}

class View2
{
	public View2(Model m)
	{
		 m.notifyViews += new Notifier(this.Update2);
	}

	void Update2(string sender)
	{
		Console.WriteLine(sender + " was changed");
	}
}

class Test 
{
	static void Main() 
	{
		Model m = new Model(); 
		new View1(m); 
		new View2(m);
		m.Change();
	}
}

[sknake]

You need to prefix your delegate declaration with an access modifier. If you have a public event that uses a delegate reference that is private to the class then other assemblies can see an event but can't access the delegate's type, thus you get the compilation error. If you have a public event, you need to expose a public delegate for that event. Add public in front of your delegate line:

using System;
using System.Data;

class Model 
{
	public delegate void Notifier(string sender);
	public event Notifier notifyViews;
	public void Change() 
	{
		notifyViews("Model");
	}
}

Likewise if you made the event private then the delegate declaration could also be private:

** This is proof of concept, You don't want this code to answer your question.

using System;
using System.Data;

class Model 
{
	private delegate void Notifier(string sender);
  private event Notifier notifyViews;
	public void Change() 
	{
		notifyViews("Model");
	}
}

[deven_a76]

Hi Scott,

I added the necessary accessifier/modifier i.e. defined public to the delegate line, still it throws error to me.

Regards
Deven.

[sknake]

Here is the complete code with two other fixes:

using System;
using System.Data;
class Model
{
  public delegate void Notifier(string sender);
  public event Notifier notifyViews;
  public void Change()
  {
    notifyViews("Model");
  }
}

class View1
{
  public View1(Model m)
  {
    m.notifyViews += new Model.Notifier(this.Update1);
  }

  void Update1(string sender)
  {
    Console.WriteLine(sender + " was changed");
  }
}

class View2
{
  public View2(Model m)
  {
    m.notifyViews += new Model.Notifier(this.Update2);
  }

  void Update2(string sender)
  {
    Console.WriteLine(sender + " was changed");
  }
}

class Test
{
  static void Main()
  {
    Model m = new Model();
    new View1(m);
    new View2(m);
    m.Change();
  }
}

[deven_a76]

Thanks sknake. It worked and the only difference I noticed that I was using the object name along with the delegate and that was causing the problem.

Thanks once again.....Sorry for the late response as saw your note today only.