Wouldn't be better if the Value property in FieldData only set the IsDirty flag to 'true' when the new value was different from the old value?
Cause the class uses generics, I've made the change as below:
public virtual T Value
{
get
{
return _data;
}
set
{
if (_data == null && value == null)
return;
if ((_data != null && !_data.Equals(value)) ||
(value != null && !value.Equals(_data)))
{
_data = value;
_isDirty = true;
}
}
}