Develop Reference

c# how to decide whether to add to sub-list or start new one

I have an sql query that provides me my data where I sometimes have lines that should be clustered (the data is aligned with an order by). The data is grouped by the field CAPName. Going through those rows line by line, I need to decide whether a new list should be initiated (content of CAPName differs to previous itteration), or whether the (already) initated list (from the previous iteration) should be added, too.
My pain lays with the location of the declaration of the relatedCapabilitySystem list.
I wanted to declare it within the if statement (Because, as I stated I need to decide whether the list from the previous iteration should be added too, or whether it should start a new list), but I can't as the compiler throws an exception, as the RLCapSys.Add(rCs); is non-existing in this content (which is only theoretically true). I understand why the compiler throws this exception. But if I declare the list on a "higher" level, than I always have a new list, which I don't want in the case that the item should be added to the list defined in the iteration(s) (1 or more) before
So what I want to achieve is, generate the list RLCapSys and add to it, in case the previous iteration contains the same CAPName (for clustering), otherwise create a new list.
SqlCommand cmdDetail = new SqlCommand(SQL_SubSytemsToCapability, DBConDetail);
SqlDataReader rdrDetail = cmdDetail.ExecuteReader();
List<relatedCapility> RLCaps = new List<relatedCapility>();
string lastCapShown = null;
while (rdrDetail.Read())
{
List<relatedCapabilitySystem> RLCapSys = new List<relatedCapabilitySystem>();
if (lastCapShown != rdrDetail["CAPName"].ToString())
{
//List<relatedCapabilitySystem> RLCapSys2 = new List<relatedCapabilitySystem>();
relatedCapility rC = new relatedCapility
{
Capability = rdrDetail["CAPName"].ToString(),
systemsRelated = RLCapSys,
};
RLCaps.Add(rC);
}
relatedCapabilitySystem rCs = new relatedCapabilitySystem
{
system = rdrDetail["name"].ToString(),
start = rdrDetail["SysStart"].ToString(),
end = rdrDetail["SysEnd"].ToString(),
};
RLCapSys.Add(rCs);
// method to compare the last related Capability shown create a new related Capabilty entry or add to the existing releated Capabilty related system list
lastCapShown = rdrDetail["CAPName"].ToString();
}
DBConDetail.Close();
and for reason of completness (but I think it is not needed here):
internal class CapabilitiesC
{
public List<Capability>Capabilities{ get;set;}
}
public class Capability
{
public string name { get; internal set; }
public string tower { get; internal set; }
public string color { get; internal set; }
public List<relatedCapility> related { get; set; }
}
public class relatedCapility
{
public string Capability { get; set; }
public List<relatedCapabilitySystem> systemsRelated { get; set; }
}
public class relatedCapabilitySystem
{
public string system { get; set; }
public string start { get; set; }
public string end { get; set; }
}

The purpose of your code is to take the input data and group it by capability. However, that is not immediately obvious. You can change your code to use LINQ so it becomes easier to understand and in the process solving your problem.
First you need a type to represent a record in your database. For lack of better name I will use Record:
class Record
{
public string System { get; set; }
public string Start { get; set; }
public string End { get; set; }
public string Capabilty { get; set; }
}
You can then create an iterator block to return all the records from the database (using an OR mapper like Entity Framework avoids most of this code and you can even shift some of the work from your computer to the database server):
IEnumerable<Record> GetRecords()
{
// Code to create connection and command (preferably in a using statement)
SqlDataReader rdrDetail = cmdDetail.ExecuteReader();
while (rdrDetail.Read())
{
yield return new Record {
System = rdrDetail["name"].ToString(),
Start = rdrDetail["SysStart"].ToString(),
End = rdrDetail["SysEnd"].ToString(),
Capability = rdrDetail["CAPName"].ToString()
};
}
// Close connection (proper using statement will do this)
}
Finally, you can use LINQ to perform the grouping:
var RLCaps = GetRecords()
.GroupBy(
record => record.Capability,
(capability, records) => new relatedCapility
{
Capability = capability ,
systemsRelated = records
.Select(record => new relatedCapabilitySystem
{
system = record.System,
start = record.Start,
end = record.End
})
.ToList()
})
.ToList();

Why not just assign it as NULL. The pattern would be
List<> myList = null;
if(condition)
{
myList = new List<>();
}
else
{
myList = previousList;
}
myList.Add();
previousList = myList;

I've got it working now. Thx everyone for your help. #martin, thx for your solution, you have put quite some effort into this, but that would have required for me to completely re-write my code. I am sure your approach would work and will be my next approach should I have a similar problem again.
It was a combination of the other answers that helped me figure it out. Let me show you what I ended up with:
SqlCommand cmdDetail = new SqlCommand(SQL_SubSytemsToCapability, DBConDetail);
SqlDataReader rdrDetail = cmdDetail.ExecuteReader();
List<relatedCapility> RLCaps = new List<relatedCapility>();
List<relatedCapabilitySystem> RLCapSys = new List<relatedCapabilitySystem>();
string lastCapShown = null;
while (rdrDetail.Read())
{
if (lastCapShown != rdrDetail["CAPName"].ToString())
{
RLCapSys = relatedCapabilitySystemList();
relatedCapility rC = new relatedCapility
{
Capability = rdrDetail["CAPName"].ToString(),
systemsRelated = RLCapSys,
};
RLCaps.Add(rC);
}
relatedCapabilitySystem rCs = new relatedCapabilitySystem
{
system = rdrDetail["name"].ToString(),
start = rdrDetail["SysStart"].ToString(),
end = rdrDetail["SysEnd"].ToString(),
};
RLCapSys.Add(rCs);
// method to compare the last related Capability shown create a new related Capabilty entry or add to the existing releated Capabilty related system list
lastCapShown = rdrDetail["CAPName"].ToString();
}
DBConDetail.Close();
So that's the section already shown bevor including my changes. Plus I added this:
private List<relatedCapabilitySystem> relatedCapabilitySystemList()
{
List<relatedCapabilitySystem> RLCapSys = new List<relatedCapabilitySystem>();
return RLCapSys;
}
Now I have new list reference everytime the CapName changes that is then added to the "higher" list. Before I had the issue of the very same list repeatedly assigned rather than a fresh one started. So thx again for your effort.

Why is my game serializing this class?

So I'm making a game, and it saves users' progress on the computer in a binary file. The User class stores a few things:
Integers for stat values (Serializable)
Strings for the Username and the skin assets
Lists of both the Achievement class and the InventoryItem class, which I have created myself.
Here are the User fields:
public string Username = "";
// ID is used for local identification, as usernames can be changed.
public int ID;
public int Coins = 0;
public List<Achievement> AchievementsCompleted = new List<Achievement>();
public List<InventoryItem> Inventory = new List<InventoryItem>();
public List<string> Skins = new List<string>();
public string CurrentSkinAsset { get; set; }
The Achievement class stores ints, bools, and strings, which are all serializable. The InventoryItem class stores its name (a string) and an InventoryAction, which is a delegate that is called when the item is used.
These are the Achievement class's fields:
public int ID = 0;
public string Name = "";
public bool Earned = false;
public string Description = "";
public string Image;
public AchievmentDifficulty Difficulty;
public int CoinsOnCompletion = 0;
public AchievementMethod OnCompletion;
public AchievementCriteria CompletionCriteria;
public bool Completed = false;
And here are the fields for the InventoryItem class:
InventoryAction actionWhenUsed;
public string Name;
public string AssetName;
The source of the InventoryAction variables are in my XNAGame class. What I mean by this is that the XNAGame class has a method called "UseSword()" or whatever, which it passes into the InventoryItem class. Previously, the methods were stored in the Game1 class, but the Game class, which Game1 inherits from, is not serializable, and there's no way for me to control that. This is why I have an XNAGame class.
I get an error when trying to serialize: "The 'SpriteFont' class is not marked as serializable", or something like that. Well, there is a SpriteFont object in my XNAGame class, and some quick tests showed that this is the source of the issue. Well, I have no control over whether or not the SpriteFont class is Serializable.
Why is the game doing this? Why must all the fields in the XNAGame class be serializable, when all I need is a few methods?
Keep in mind when answering that I'm 13, and may not understand all the terms you're using. If you need any code samples, I'll be glad to provide them for you. Thanks in advance!
EDIT: One solution I have thought of is to store the InventoryAction delegates in a Dictionary, except that this will be a pain and isn't very good programming practice. If this is the only way, I'll accept it, though (Honestly at this point I think this is the best solution).
EDIT 2: Here's the code for the User.Serialize method (I know what I'm doing in inefficient, and I should use a database, blah, blah, blah. I'm fine with what I'm doing now, so bear with me.):
FileStream fileStream = null;
List<User> users;
BinaryFormatter binaryFormatter = new BinaryFormatter();
try
{
if (File.Exists(FILE_PATH) && !IsFileLocked(FILE_PATH))
{
fileStream = File.Open(FILE_PATH, FileMode.Open);
users = (List<User>)binaryFormatter.Deserialize(fileStream);
}
else
{
fileStream = File.Create(FILE_PATH);
users = new List<User>();
}
for (int i = 0; i < users.Count; i++)
{
if (users[i].ID == this.ID)
{
users.Remove(users[i]);
}
}
foreach (Achievement a in AchievementsCompleted)
{
if (a.CompletionCriteria != null)
{
a.CompletionCriteria = null;
}
if (a.OnCompletion != null)
{
a.OnCompletion = null;
}
}
users.Add(this);
fileStream.Position = 0;
binaryFormatter.Serialize(fileStream, users);

You cannot serialize a SpriteFont by design, actually this is possible (.XNB file) but it hasn't been made public.
Solution:
Strip it off your serialized class.
Alternatives:
If for some reasons you must serialize some font, the first thing that comes to my mind would be to roll-out your own font system such as BMFont but that's a daunting task since you'll have to use it everywhere else where you might already do ...
Generate a pre-defined amount of fonts (i.e. Arial/Times/Courier at size 10/11/12 etc ...) using XNA Content app (can't recall its exact name); then store this user preference as two strings. With a string.Format(...) you should be able to load the right font back quite easily.
Alternative 2 is certainly the easiest and won't take more than a few minutes to roll-out.
EDIT
Basically, instead of saving a delegate I do the following:
inventory items have their own type
each type name is de/serialized accordingly
their logic does not happen in the main game class anymore
you don't have to manually match item type / action method
So while you'll end up with more classes, you have concerns separated and you can keep your main loop clean and relatively generic.
Code:
public static class Demo
{
public static void DemoCode()
{
// create new profile
var profile = new UserProfile
{
Name = "Bill",
Gold = 1000000,
Achievements = new List<Achievement>(new[]
{
Achievement.Warrior
}),
Inventory = new Inventory(new[]
{
new FireSpell()
})
};
// save it
using (var stream = File.Create("profile.bin"))
{
var formatter = new BinaryFormatter();
formatter.Serialize(stream, profile);
}
// load it
using (var stream = File.OpenRead("profile.bin"))
{
var formatter = new BinaryFormatter();
var deserialize = formatter.Deserialize(stream);
var userProfile = (UserProfile) deserialize;
// set everything on fire :)
var fireSpell = userProfile.Inventory.Items.OfType<FireSpell>().FirstOrDefault();
if (fireSpell != null) fireSpell.Execute("whatever");
}
}
}
[Serializable]
public sealed class UserProfile
{
public string Name { get; set; }
public int Gold { get; set; }
public List<Achievement> Achievements { get; set; }
public Inventory Inventory { get; set; }
}
public enum Achievement
{
Warrior
}
[Serializable]
public sealed class Inventory : ISerializable
{
public Inventory() // for serialization
{
}
public Inventory(SerializationInfo info, StreamingContext context) // for serialization
{
var value = (string) info.GetValue("Items", typeof(string));
var strings = value.Split(';');
var items = strings.Select(s =>
{
var type = Type.GetType(s);
if (type == null) throw new ArgumentNullException(nameof(type));
var instance = Activator.CreateInstance(type);
var item = instance as InventoryItem;
return item;
}).ToArray();
Items = new List<InventoryItem>(items);
}
public Inventory(IEnumerable<InventoryItem> items)
{
if (items == null) throw new ArgumentNullException(nameof(items));
Items = new List<InventoryItem>(items);
}
public List<InventoryItem> Items { get; }
#region ISerializable Members
public void GetObjectData(SerializationInfo info, StreamingContext context)
{
var strings = Items.Select(s => s.GetType().AssemblyQualifiedName).ToArray();
var value = string.Join(";", strings);
info.AddValue("Items", value);
}
#endregion
}
public abstract class InventoryItem
{
public abstract void Execute(params object[] objects);
}
public abstract class Spell : InventoryItem
{
}
public sealed class FireSpell : Spell
{
public override void Execute(params object[] objects)
{
// using 'params object[]' a simple and generic way to pass things if any, i.e.
// var world = objects[0];
// var strength = objects[1];
// now do something with these !
}
}

Okay, so I figured it out.
The best solution was to use a Dictionary in the XNAGame class, which stores two things: an ItemType (an enumeration), and an InventoryAction. Basically, when I use an item, I check it's type and then look up it's method. Thanks to everyone who tried, and I'm sorry if the question was confusing.

Looping to Create and Add New Objects to ArrayList

Edit to save you from reading through this whole post
tldr: an object's fields should not be static unless you want all instances of that object to have the same value for that field
I'm trying to create and populate an ArrayList of Blog objects. I do know the generic way do this:
create ArrayList of Blogs
loop (some condition)
create new Blog
add this Blog to AL
However, when I attempt to do so within the while(datareader.read()) loop, all of the elements in the ArrayList are exactly the same Blog. Specifically, I end up with an ArrayList filled with multiple pointers to the very last Blog object from the database table. Here is my code:
public static ArrayList AllBlogs()
{
SqlDataReader dr = anonPage.ExecuteReader("SELECT * FROM Kristina_Blogs");
ArrayList allBlogs = new ArrayList();
if (dr.HasRows)
{
while (dr.Read())
{
Blog b = new Blog();
//grab a row from Kristina_Blogs and assign those attributes to b
b.setTitle(dr["title"].ToString());
b.setMessage(dr["message"].ToString());
b.setId(dr["id"]);
allBlogs.Add(b);
}
}
dr.Close();
return allBlogs;
}
As I said before, the result of this is an ArrayList filled with pointers to the very last blog from the Kristina_Blogs table. I imagine the ArrayList allBlogs looks like [b, b, b, ... b] and therefore they ALL get updated when I say b.setTitle() etc. But how can this be the case if I am creating a NEW Blog object at the beginning of each iteration?
Here is some extra info that you don't have to read but it might clear up some confusion about the structure of the problem:
Blog object has id, title, and message fields and their respective getter/setters
Kristina_Blogs is a table representing these blogs with columns for id, title, message
The suggestions say to include a tag for my DB engine but I can't find a tag for it: Microsoft SQL Server Management Studio
This code works perfectly when I use an ArrayList of Strings instead of Blogs
Edit: Including the code from Blog class
public class Blog
{
public App myApp;
public static string Title;
public static string Message;
public static int Id;
//constructors
public Blog() { }
public Blog(App App) { this.myApp = App; }
//all getters and setters look like this
public string getTitle() { return Title; }
public void setTitle(string t) { Title = t; }
}

The main problem you have, as I mentioned in comments is your member variables are static, so when you set the value, they change in all instances. you should change your code this way:
public class Blog
{
public int Id { get; set; }
public string Title { get; set; }
public string Message { get; set; }
}
And fill your list this way, don't forget to add using System.Linq;:
var result = new List<Blog>();
var connection = #"your connection string";
var command = "SELECT * FROM Kristina_Blogs";
var adapter = new System.Data.SqlClient.SqlDataAdapter(command, connection);
var dataTable = new DataTable();
//Get data
adapter.Fill(dataTable);
dataTable.Rows.Cast<DataRow>().ToList()
.ForEach(row =>
{
var b = new Blog();
b.Id = row.Field<int>("Id");
b.Title = row.Field<string>("Title");
b.Message = row.Field<string>("Message");
result.Add(b);
});
return result;
Note:
When you create a member static, it is shared between all instances of that calss.
In C# you can use property to get or set values, you don't need to setX or setY, when you get the value of a property, the get code of that property will execute and when you assign a value to a property the set part of it will execute. you can define properties this way:
Property:
private int id;
public int Id
{
get
{
return id;
}
set
{
id = value;
}
}
or more simple:
public int Id { get; set; }

All of the fields in your Blog class are static, meaning they're shared between all object instances. You want them to be instance field (meaning not static) so that each object has its own copy of each of those values.

Remove the static attributes from your class:
public class Blog
{
public App myApp;
public String Title;
public String Message;
public int Id;
//constructors
public Blog() { }
public Blog(App App) { this.myApp = App; }
//all getters and setters look like this
public String getTitle() { return Title; }
public String getMessage() { return Message; }
public void setTitle(String t) { Title = t; }
public void setMessage(String m) { Message = m; }
}
When you use static variables, all instances of an object will contain the same values in those variables. By removing the static keyword, you are allowing different instances of the object to hold different values.
Now, every time you create a blog object, that object's Title and Message etc, will contain its own information.

I would make a quick method to prevent null value from throwing error
public static string GetSafeString(SqlDataReader reader, int index)
{
if (!reader.IsDBNull(index))
return reader.GetString(index);
else
return string.Empty;
}
Replace this code:
while (dr.Read())
{
Blog b = new Blog();
//grab a row from Kristina_Blogs and assign those attributes to b
b.setTitle(dr["title"].ToString());
b.setMessage(dr["message"].ToString());
b.setId(dr["id"]);
allBlogs.Add(b);
}
With This Code:
while (dr.Read())
{
Blog b = new Blog();
//grab a row from Kristina_Blogs and assign those attributes to b
b.setId(dr.GetInt32(0));
b.setTitle(GetSafeString(dr, 1);
b.setMessage(GetSafeString(dr, 2);
allBlogs.Add(b);
}
Where the number is the index of field in the record and assuming "id" is an integer. Also consider moving creation of "Blog" object outside of loop and just change values.

Cloning Complex Object having DataTable and other object as property in C#

I want to deep copy of my complex C# object having DataTable as property.It is throwing error as "Table SalesData does not belong to this DataSet."
Here is my C# object:
public class Foo
{
public VehicleDetails VehicleDetails { get; set; }
public VehicleCondition VehicleCondition { get; set; }
public string Zipcode { get; set; }
public string StateCode { get; set; }
public DataTable SalesData { get; set; }
public DataTable OtherDataTable { get; set; }
}
I have used following code to clone object:
public static T CloneFullObject<T>(T i)
{
if (Object.ReferenceEquals(i, null)) return default(T);
var x = new XmlSerializer(i.GetType());
using (var m = new MemoryStream())
{
x.Serialize(m, i);
m.Seek(0, SeekOrigin.Begin);
return (T)x.Deserialize(m);
}
}
I am creating object as:
Foo foo = new Foo();
VehicleDetails vehicleDetail = new VehicleDetails();
// Fill vehicleDetail object
VehicleCondition vehicleCondition = new VehicleCondition ();
// Fill vehicleCondition object
foo.VehicleDetails = vehicleDetail;
foo.VehicleCondition = vehicleCondition;
DataTable salesData = getDataTable();
salesData.TableName = "salesData";
foo.SalesData = salesData;
DataTable otherData = getDataTable();
salesData.TableName = "otherData";
foo.OtherDataTable = salesData;
Below code is throwing error as:
System.InvalidOperationException: There was an error generating the XML document. ---> System.ArgumentException: Table salesData does not belong to this DataSet.
Foo clonefullObject = CloneFullObject(foo);
Please help if I am missing something before cloning object.
Note: both Datatable have value and it's not null.
Edit:
class Foo have some complex properties like:
private int _mileage;
public void SetMileage(int mileage) { _mileage = mileage; }
private int _expectedMileage;
public void SetExpectedMileage(int mileage) { _expectedMileage = mileage; }
public int GetMileage(bool flag)
{
return (flag)
? _mileage
: Math.Max(_mileage, _expectedMileage);
}

When cloning/copying objects you can simply clone/copy them. Serializing is quite expensive overkill, especially when implemented without concern for performance (you can read more in this SE question).
However, serialization is not your real problem, copying DataTable with both structure and data is. And it appears that your problem is not really your problem, your approach to it is your problem. DataTable.Copy() does all of that.
So how to do it? Well, how about properly?
On of proper approaches would be to implement ICloneable interface. It is kind of clumsy as return type is object. By implementing it on sub classes you can chain it deeper. I used as for casting in sample, have in mind that it will not generate exception on type mismatch. (As usually you can read more on some old SE question). You might, or might not, want to generate exceptions on faulty state (null) of DataTables.
public class Foo : ICloneable
{
//some fields....
private int _Bar; //private field
public void SetBar(int value) { _Bar = value; } //Field setter
public object Clone()
{
var result = new Foo()
{
_Bar = _Bar, // private members are accessible from their scope, even when object is different
Zipcode = Zipcode,
StateCode = StateCode,
SalesData = SalesData== null ? null : SalesData.Copy(),
OtherDataTable = OtherDataTable == null ? null : OtherDataTable.Copy(),
VehicleDetails = VehicleDetails.Clone() as VehicleDetails,
VehicleCondition = VehicleCondition.Clone() as VehicleCondition,
};
// alternatively you can call setter methods
result.SetBar(_Bar);
return result;
}
}
Notes:
You should work on creating object in better style, for example using Factory or at least use Object Initializer or constructor.
#SergeyBerezovskiy made a valid point by suggesting data model classes instead of full data tables.

How to compare two distinctly different objects with similar properties

This is all in C#, using .NET 2.0.
I have two lists of objects. They are not related objects, but they do have certain things in common that can be compared, such as a GUID-based unique identifier. These two lists need to be filtered by another list which just contains GUIDs which may or may not match up with the IDs contained in the first two lists.
I have thought about the idea of casting each object list to just object and sorting by that, but I'm not sure that I'll be able to access the ID property once it's cast, and I'm thinking that the method to sort the two lists should be somewhat dumb in knowing what the list to be sorted is.
What would be the best way to bring in each object list so that it can be sorted against the list with only the IDs?

You should make each of your different objects implement a common interface. Then create an IComparer<T> for that interface and use it in your sort.

Okay, if you have access to modify your original classes only to add the interface there, Matthew had it spot on. I went a little crazy here and defined out a full solution using 2.0 anonymous delegates. (I think I'm way addicted to 3.0 Lambda; otherwise, I probably would've written this out in foreach loops if I was using 2005 still).
Basically, create an interface with the common properties. Make yoru two classes implement the interface. Create a common list casted as the interface, cast and rip the values into the new list; remove any unmatched items.
//Program Output:
List1:
206aa77c-8259-428b-a4a0-0e005d8b016c
64f71cc9-596d-4cb8-9eb3-35da3b96f583
List2:
10382452-a7fe-4307-ae4c-41580dc69146
97f3f3f6-6e64-4109-9737-cb72280bc112
64f71cc9-596d-4cb8-9eb3-35da3b96f583
Matches:
64f71cc9-596d-4cb8-9eb3-35da3b96f583
Press any key to continue . . .
using System;
using System.Collections.Generic;
using System.Text;
namespace ConsoleApplication8
{
class Program
{
static void Main(string[] args)
{
//test initialization
List<ClassTypeA> list1 = new List<ClassTypeA>();
List<ClassTypeB> list2 = new List<ClassTypeB>();
ClassTypeA citem = new ClassTypeA();
ClassTypeB citem2 = new ClassTypeB();
citem2.ID = citem.ID;
list1.Add(new ClassTypeA());
list1.Add(citem);
list2.Add(new ClassTypeB());
list2.Add(new ClassTypeB());
list2.Add(citem2);
//new common list.
List<ICommonTypeMakeUpYourOwnName> common_list =
new List<ICommonTypeMakeUpYourOwnName>();
//in english, give me everything in list 1
//and cast it to the interface
common_list.AddRange(
list1.ConvertAll<ICommonTypeMakeUpYourOwnName>(delegate(
ClassTypeA x) { return (ICommonTypeMakeUpYourOwnName)x; }));
//in english, give me all the items in the
//common list that don't exist in list2 and remove them.
common_list.RemoveAll(delegate(ICommonTypeMakeUpYourOwnName x)
{ return list2.Find(delegate(ClassTypeB y)
{return y.ID == x.ID;}) == null; });
//show list1
Console.WriteLine("List1:");
foreach (ClassTypeA item in list1)
{
Console.WriteLine(item.ID);
}
//show list2
Console.WriteLine("\nList2:");
foreach (ClassTypeB item in list2)
{
Console.WriteLine(item.ID);
}
//show the common items
Console.WriteLine("\nMatches:");
foreach (ICommonTypeMakeUpYourOwnName item in common_list)
{
Console.WriteLine(item.ID);
}
}
}
interface ICommonTypeMakeUpYourOwnName
{
Guid ID { get; set; }
}
class ClassTypeA : ICommonTypeMakeUpYourOwnName
{
Guid _ID;
public Guid ID {get { return _ID; } set { _ID = value;}}
int _Stuff1;
public int Stuff1 {get { return _Stuff1; } set { _Stuff1 = value;}}
string _Stuff2;
public string Stuff2 {get { return _Stuff2; } set { _Stuff2 = value;}}
public ClassTypeA()
{
this.ID = Guid.NewGuid();
}
}
class ClassTypeB : ICommonTypeMakeUpYourOwnName
{
Guid _ID;
public Guid ID {get { return _ID; } set { _ID = value;}}
int _Stuff3;
public int Stuff3 {get { return _Stuff3; } set { _Stuff3 = value;}}
string _Stuff4;
public string Stuff4 {get { return _Stuff4; } set { _Stuff4 = value;}}
public ClassTypeB()
{
this.ID = Guid.NewGuid();
}
}
}

Using only .NET 2.0 methods:
class Foo
{
public Guid Guid { get; }
}
List<Foo> GetFooSubset(List<Foo> foos, List<Guid> guids)
{
return foos.FindAll(foo => guids.Contains(foo.Guid));
}
If your classes don't implement a common interface, you'll have to implement GetFooSubset for each type individually.

I'm not sure that I fully understand what you want, but you can use linq to select out the matching items from the lists as well as sorting them. Here is a simple example where the values from one list are filtered on another and sorted.
List<int> itemList = new List<int>() { 9,6,3,4,5,2,7,8,1 };
List<int> filterList = new List<int>() { 2, 6, 9 };
IEnumerable<int> filtered = itemList.SelectMany(item => filterList.Where(filter => filter == item)).OrderBy(p => p);

I haven't had a chance to use AutoMapper yet, but from what you describe you wish to check it out. From Jimmy Bogard's post:
AutoMapper conventions
Since AutoMapper flattens, it will
look for:
Matching property names
Nested property names (Product.Name
maps to ProductName, by assuming a
PascalCase naming convention)
Methods starting with the word “Get”,
so GetTotal() maps to Total
Any existing type map already
configured
Basically, if you removed all the
“dots” and “Gets”, AutoMapper will
match property names. Right now,
AutoMapper does not fail on mismatched
types, but for some other reasons.

I am not totally sure what you want as your end results, however....
If you are comparing the properties on two different types you could project the property names and corresponding values into two dictionaries. And with that information do some sort of sorting/difference of the property values.
Guid newGuid = Guid.NewGuid();
var classA = new ClassA{Id = newGuid};
var classB = new ClassB{Id = newGuid};
PropertyInfo[] classAProperties = classA.GetType().GetProperties();
Dictionary<string, object> classAPropertyValue = classAProperties.ToDictionary(pName => pName.Name,
pValue =>
pValue.GetValue(classA, null));
PropertyInfo[] classBProperties = classB.GetType().GetProperties();
Dictionary<string, object> classBPropetyValue = classBProperties.ToDictionary(pName => pName.Name,
pValue =>
pValue.GetValue(classB, null));
internal class ClassB
{
public Guid Id { get; set; }
}
internal class ClassA
{
public Guid Id { get; set; }
}
classAPropertyValue
Count = 1
[0]: {[Id, d0093d33-a59b-4537-bde9-67db324cf7f6]}
classBPropetyValue
Count = 1
[0]: {[Id, d0093d33-a59b-4537-bde9-67db324cf7f6]}

Thist should essentially get you what you want - but you may be better of using linq
class T1
{
public T1(Guid g, string n) { Guid = g; MyName = n; }
public Guid Guid { get; set; }
public string MyName { get; set; }
}
class T2
{
public T2(Guid g, string n) { ID = g; Name = n; }
public Guid ID { get; set; }
public string Name { get; set; }
}
class Test
{
public void Run()
{
Guid G1 = Guid.NewGuid();
Guid G2 = Guid.NewGuid();
Guid G3 = Guid.NewGuid();
List<T1> t1s = new List<T1>() {
new T1(G1, "one"),
new T1(G2, "two"),
new T1(G3, "three")
};
List<Guid> filter = new List<Guid>() { G2, G3};
List<T1> filteredValues1 = t1s.FindAll(delegate(T1 item)
{
return filter.Contains(item.Guid);
});
List<T1> filteredValues2 = t1s.FindAll(o1 => filter.Contains(o1.Guid));
}
}