Comments on: Only allowing certain types to set a property

By: jdvolz

jdvolz — Fri, 20 Jan 2006 02:36:33 +0000

Could you just use the get portion of the property and then write accessor methods for the internal data of the data base object? Something like:

public class MyDBObject
{
private bool isDirty = false;
public bool IsDirty
{
return this.isDirty;
}

//modifiers
public void SetValue(object someValue)
{
….//set the value within the data structure and then…
this.isDitry = true;
}

}

This method assumes that you are creating a layer of abstraction in the object, and only allowing the object to alter the data that is internal to it (called encapsulation I believe). I believe this is how DataSets keep track of the state of rows contained within them.

By: Anonymous

Anonymous — Wed, 18 Jan 2006 18:09:28 +0000

Of all the comments here, I agree with Jeremy D. Miller. I like the idea of having a seperate object – perhaps the persistor itself – keeping track of the isdirty. The easy way to implement this is to have the DTO raise a MemberChanged event whenever a Set is called, and your listener object sets the isdirty flag on its own. then when your persistor comes along, it reads the isdirty from the listener object to determine whether or not it needs to update that object to the database. Doing this allows you to control which object your persistor pays attention to, to get the isdirty flag.

By: Anonymous

Anonymous — Wed, 18 Jan 2006 16:44:36 +0000

perhaps ….

MyDatabaseClass {
protected bool isDirty
}

MyDirtyDatabaseClass : MyDatabaseClass {
public bool isDirty {
get { return isDirty }
set { isDirty = value}
}
}

MyDatabaseClass MyDatabaseClassFactory() {
return (MyDatabaseClass) new MyDirtyDatabaseClass();
}

By: Anonymous

Anonymous — Wed, 18 Jan 2006 15:27:17 +0000

If you really want to do this with 1.1, have a look at StrongNameIdentityPermission.

http://msmvps.com/blogs/manoj/archive/2004/10/20/16208.aspx

By: Anonymous

Anonymous — Wed, 18 Jan 2006 14:05:21 +0000

Sorry, messed that up:

PersistanceClass: IPersistStuff
{
public void PersistMyClass(MyClass class);
}

MyClass
{
private bool isDirty;
public void Persist(IPersistStuff persistStuff)
{
if (isDirty)
PersistMyClass(this);
isDirty = false;
}
}

By: Anonymous

Anonymous — Wed, 18 Jan 2006 14:01:21 +0000

It’s hard to know for sure without knowing the code, but maybe something like this?:

PersistanceClass: IPersistStuff
{
public void PersistMyClass(MyClass class);
}

MyClass
{
private bool isDirty;
public void Persist(IPersistStuff persistStuff)
{
if (isDirty)
persistStuff(this);
isDirty =false;
}
}

By: johnwood

johnwood — Wed, 18 Jan 2006 13:03:50 +0000

Ben,
You can implement Scott’s suggestion in .Net 1.1 simply by having two methods to get and set the field rather than a property. Just make the setter method internal and the getter method public.

John W

By: breichelt

breichelt — Wed, 18 Jan 2006 11:08:16 +0000

wow, lots of comments

Scott & John: I didnt know that you could selectively place the internal keyword on getters and setters like that in .net 2.0. Unfortunately, this is .net 1.1, and, for that matter, the classes are not in the same assembly. The persistor is part of the common base assembly, and the dto is a business object, in another assembly. Good tidbit to know though.

Jeremy: thats a good idea, one that I will explore

Craig: I also like your suggestion, it seems pretty easy, I’ll have to see if it would be viable, may have to make a new interface, which is no big deal

By: Anonymous

Anonymous — Wed, 18 Jan 2006 10:45:49 +0000

I second Scott’s suggestion of the internal setter; hopefully they share an assembly…

By: Anonymous

Anonymous — Wed, 18 Jan 2006 10:19:18 +0000

I’d use:

public bool IsDirty
{
get { return _isDirty; }
internal set { _isDirty = value; }
}

(C# 2.0 only). Now I’ve restricted the setter visibility to types inside the same assembly. This may be restrictive enough for you depending on where the Persistor and other types live….