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

[C# Programming]

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); }}