Error 1 The modifier 'abstract' is not valid for this item

[RaoulICT]

I'm trying to build my C# project, I get the error: The modifier 'abstract' is not valid for this item Is the item: FieldChanged; In the following Interface:

namespace program.Drawing.Fields
{
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;

public interface IFieldHolder
{

abstract event FieldChangedEventHandler FieldChanged;

void AddField(Field field);
Field GetField(FieldType fieldType);
List GetFields();
bool HasField(FieldType fieldType);
void RemoveField(Field field);
void SetFieldValue(FieldType fieldType, object value);
}
}

[Trak4Net]

Have a read at the link below

Quote:

•Abstract method declarations are only permitted in abstract classes.

Quote:

Interfaces and interface members are abstract;

http://msdn.microsoft.com/en-us/library/sf985hc5(v=vs.71).aspx[^] and here http://msdn.microsoft.com/en-us/library/ms173156.aspx[^]

[RaoulICT]

Can you gave me a fix in my code

[Trak4Net]

You just need to remove the abstract declaration for the event.

namespace program.Drawing.Fields
{
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;

public interface IFieldHolder
{
  event FieldChangedEventHandler FieldChanged;

  void AddField(Field field);
  Field GetField(FieldType fieldType);
  List<Field> GetFields();
  bool HasField(FieldType fieldType);
  void RemoveField(Field field);
  void SetFieldValue(FieldType fieldType, object value);
}

}

[BobJanova]

Just to expand slightly on the (correct) fix already posted: You can't put 'public' or 'abstract' on interface members, because by definition they are already public and abstract, so to prevent confusion* no access modifiers are permitted. *: or that's what the rationale is, anyway. I think it's silly, it prevents future expansion and the fact that the default scope (public abstract) in an interface is different from that (private) in a class is more confusing than making you write 'public abstract' on things in interfaces.

[PIEBALDconsult]

I think it makes sense that everything in an Interface is public and abstract by definition, but I don't like default modifiers on class members.

[Luc Pattyn]

:thumbsup:

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