/// <summary>
/// Determine whether this entity is equal to another entity.
/// </summary>
/// <param name="other">The entity to compare to this entity when determining equality.</param>
/// <returns>True if the other entity is not null, neither entity is transient, and both
/// entities share the same Id value.</returns>
public virtual bool Equals(DbEntityWithId <TId> other)
{
// instance is never equal to null
if (other == null)
{
return(false);
}
// when references are equal, they are the same object
if (ReferenceEquals(this, other))
{
return(true);
}
// when either object is transient or the id's are not equal, return false
if (IsTransient(this) || IsTransient(other) || !Equals(Id, other.Id))
{
return(false);
}
// when the id's are equal and neither object is transient
// return true when one can be cast to the other
// because this entity could be generated by a proxy
var otherType = other.GetUnproxiedType();
var thisType = GetUnproxiedType();
return(thisType.IsAssignableFrom(otherType) || otherType.IsAssignableFrom(thisType));
}
private static bool IsTransient(DbEntityWithId <TId> obj)
{
// an object is transient when its id is the default (null for strings or 0 for numbers)
return(Equals(obj.Id, default(TId)));
}