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There isn't much of a point if you have to include the server implementation with the client. But it is possible to split it up so you'd have 3 assemblies:
Shared - contains interfaces or base classes implemented by "Server"
Server - references "Shared" and implements "Shared" assembly's interfaces or base classes
Client - references "Shared"
If you want a ton of information about remoting you should get Ingo Rammer's book, Advanced .NET Remoting. I'm on Chapter 4 now and I've been really impressed with it. You can get chapter 2 from his website[^] which covers the basics of remoting, while chapter 3 shows some caveats to what was shown in chapter 2 and offers ways through and around them.
Chapter 4 so far is concentrating on how to use configuration files to get around having to hard code everything in the server/client.
James
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972
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oooo... there're too many books that I need to read in too little time....
life's short, ....
anyway, QUOTE:
Shared - contains interfaces or base classes implemented by "Server"
Server - references "Shared" and implements "Shared" assembly's interfaces or base classes
Client - references "Shared"
QUESTION: so, basically, you have two dll and two exe:
1. RemoteObject.dll
2. Interface assembly of remote object (RemoteObjInterface.dll)
3. Server (RemoteObjServer.exe):
a. References the interface assembly (2)
b. Register channel, register type.
4. Client (RemoteClient.exe):
a. References Interface assembly (2)
b. Do you still use Activator.GetObject()?
Just thinking how to implement interface.. By the way, you still need to refernce interface assembly. I guess the point of remoting is that RemoteObject do run in different process/app context/server - meaning it has access to resources on a remote server (database/file/AD/registry...etc). if it wasn't that, there's not much of a point for remoting (am i missing something here?)
norm
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norm wrote:
Do you still use Activator.GetObject()?
Yes/no, for certain remoting scenarios you use it; in other cases you can use configuration files and some generated wrappers to get around it.
norm wrote:
meaning it has access to resources on a remote server (database/file/AD/registry...etc). if it wasn't that, there's not much of a point for remoting (am i missing something here?)
Another use is to have a single place to keep your code up to date. For example, you could use remoting to host a business rules library or data access library. If rules change you can update the assembly on the server but not have to update each client.
Another would be to simply keep your code from even being on the client computer. This is similar to the web service approach, but you don't have to host through a web server.
James
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972
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Thanks. But I'm having some trouble separating interface with remote class. Calls to:
SERVER SIDE:
RemotingConfiguration.RegisterWellKnownServiceType(
typeof(nsCRemoteObj.CRemoteObj), //QUESTION 1: I still need to reference the remote object - as opposed to the interface??
"CRemoteObjURI",
WellKnownObjectMode.SingleCall //QUESTION 2: Since we'll be communicating with client via "interface", NO Singleton?
);
AND
CLIENT SIDE:
IRemoteObj obj = (IRemoteObj) Activator.GetObject(
typeof(CRemoteObj), //QUESTION 3: Opps, I still to reference the remote object assembly - in addition to interface assembly!??
"http://localhost:8085/CRemoteObjURI"
);
Any idea?
**********************************************************************
code structure below if you're interested. (Questions are highlited --> "QUESTION"):
(1) my remote object source file (CRemoteObj.cs) (dll):
using nsCRemoteObjInterface; //For IRemoteObj interface.
namespace nsCRemoteObj
{
public class CRemoteObj : System.MarshalByRefObject, IRemoteObj
{
... some stuff ...
}
}
Then, "add reference" to reference the interface assembly (CRemoteObjInterface.cs).
(2) Interface assembly (CRemoteObjInterface.cs) (dll):
using System;
namespace nsCRemoteObjInterface
{
public interface IRemoteObj : IMarshal
{
bool AuthenticateLoser(string sUserName, string sPasswd);
};
}
Nothing needs to be referenced from interface assembly.
(3) Server "CRemoteObjServer.cs" (exe):
{
[STAThread]
static void Main(string[] args)
{
//Register channel:
TcpServerChannel tcpchannel = new TcpServerChannel(8086);
ChannelServices.RegisterChannel(tcpchannel);
HttpServerChannel httpchannel = new HttpServerChannel(8085);
ChannelServices.RegisterChannel(httpchannel);
//Register TYPE:
RemotingConfiguration.RegisterWellKnownServiceType(
typeof(nsCRemoteObj.CRemoteObj), //QUESTION 1: I still need to reference the remote object - as opposed to the interface??
"CRemoteObjURI",
WellKnownObjectMode.SingleCall //QUESTION 2: Since we'll be communicating with client via "interface", NO Singleton?
);
Console.WriteLine("CRemoteServer started and listening on tcp(8086) and http(8085).");
Console.WriteLine("Hit any key to exit.");
Console.WriteLine();
Console.ReadLine();
}
(4) Client "CRemoteObjClient.cs" (exe):
using nsCRemoteObj; //QUESTION 3: Still need to reference remote object assembly in addition to interface assembly...
using nsCRemoteObjInterface;
namespace nsCRemoteObjClient
{
class CRemoteObjClient
{
[STAThread]
static void Main(string[] args)
{
//Register channel:
ChannelServices.RegisterChannel( new HttpChannel() );
try
{
//Retrieve remote object proxy (WellKnown object - server-activated SingleCall):
IRemoteObj obj = (IRemoteObj) Activator.GetObject(
typeof(CRemoteObj),
"http://localhost:8085/CRemoteObjURI"
);
//Invoke function thru proxy:
Console.WriteLine("CRemoteObjClient: Client side invoke.");
bool bAuthStatus = false;
for(int i=0; i<3; i++)
{
bAuthStatus = obj.AuthenticateLoser("Paul", "12345");
Console.WriteLine("i={0}, bAuthStatus: {1}", i.ToString(), bAuthStatus);
}
}
catch(Exception err)
{
Console.WriteLine("Exception: {0}", err.ToString());
}
}
}
}
norm
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Q1: Yes, you publish the object implementing your shared interface
Q2: No, you can use Singleton mode as well as SingleCall
Q3: You don't have to reference the server assembly, just the shared assembly because your client code should look something like:
try
{
IRemoteObj obj = (IRemoteObj) Activator.GetObject(
typeof(IRemoteObj),
"http://localhost:8085/CRemoteObjURI"
);
...The Type passed in is simply to tell the Activator what type of object it should marshal back and forth between server and client. Your specific object is specified by the second parameter which includes the name for that object.
Hope that makes some sense,
James
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972
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Okay, it's working now, thanks a lot!
On server side:
RemotingConfiguration.RegisterWellKnownServiceType(
typeof(nsCRemoteObj.CRemoteObj),
"CRemoteObjURI",
WellKnownObjectMode.SingleCall
);
On client side:
RemoteObj obj = (IRemoteObj) Activator.GetObject(
typeof(IRemoteObj),
"http://localhost:8085/CRemoteObjURI"
);
One more QUESTION: Alrite, we're using interface. Just why however, we can only use server-activated, and NOT client-activated?
norm
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norm wrote:
Just why however, we can only use server-activated, and NOT client-activated?
When you're using an interface a client-activated method would require you to do:
IRemoteObj obj = new IRemoteObj(); But you can't create an instance of an interface. So in order to use a CAO it would require you to switch from using an interface to using a base class, the downside to this is that the CAO won't let you use non-default constructors. And then it gets worse... Typically your base class is declared as abstract, but if the class is abstract then you can't use the new operator again because you can't create instances of abstract classes.
As you can see, it is rather confusing. That is why I highly recommend picking up Ingo's book, because it lays out a lot of this information for you. I don't have the book in front of me, but I think a lot of chapter 3 focuses on this topic.
James
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972
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Back in the good old VB6 there where the Shape and the Line controls, which were very useful. They seemed to disappear in the VB7 and the C#. Does any one know what happened to them?
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dshay1 wrote:
Does any one know what happened to them?
AFAIK they disappeared by design. That is that you must paint your own line with GDI+. I don't think this is a great shift back. One may think about creating a control that behaves similar to the VB6 controls. Besides they were easy to use, they had one big caveat: They were full blown objects, with all the memory consumption.
Try searching codeproject.com for examples on GDI+. You will find how to draw a line - and four lines make a shape 
Sascha
--
http://www.livingit.de
http://www.mobile-bookmarks.info
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In the words of ME
THANK GOD
just use the GDI+ its more reliable on exact positions than those controls ever were
I'm not an expert yet, but I play one at work. Yeah and here too.
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I am just reading up on remoting, and I figure it'd nice to be able to expose remoting object thru web service. Unfortunately, the book i'm reading have very little information on this. The following is what I do know, hope someone can add to that:
1. Server side:
a.create virtual directory
b. modify web.config to add remoting configurations, such as <wellknown...>
c. make sure assembly of remoting object is under /bin directory of the virtual directory.
d. make sure IIS is running.
QUESTIONs:
1a. Do we need to create a "WebService" to host this remote object? I understand ASP.NET is responsible for channel registration and web.config has the information on what remoting object is hosted. But anything else in addition?
1b. Web.config:
<wellknown mode="SingleCall"
type="XXX.YYYYY.MyRemoteObjClass, MyRemoteObjClassAssemblyName",
objectUri="RemoteObjAssembly.soap"
/>
1b-1. What's objectUri?? Why is it not:
"http://localhost/MyRemoteObjClass.dll" instead?
1b-2. Why "soap" file as opposed to a dll?
1b-3. How can you create this SOAP file?? Do you have to script it yourself?
1b-4. MyRemoteObjClassAssemblyName is the "assembly name" --> meaning, "file name" of the assembly of remote object class? In the assembly info file, there's [assembly: AssemblyTitle("")], but nothing that you can do to specify "assembly name".
2. Client side:
a. create a client app (C#, win app, console app, anything)
b. configure remoting by configuring client's application config file. Specify what remoting object you wish to connect to.
For example: ClientApp.config
<configuration>
<system.runtime.remoting>
<application>
<client url="http://localhost/MyVirtualDirName"> //QUESTION 2b-1: What if there're more than one assembly in the virtual directory?
<wellknown
type="XXX.YYY.MyRemoteObjClass,
MyRemoteObjClassAssemblyName"
url="http://localhost/MyVirtualDirName"
/>
</client>
</application>
</system.runtime.remoting>
</configuration>
QUESTION 2-b-2: Do we need to "Add-web-reference" or just "add reference" to the assembly of Remote object class (MyRemoteObjClass.dll)??
QUESTION 2-b-3: I understand that for remoting/ASP.NET, we only get stateless wellknown or server-activated objects --> So, we get to instantiate the object with either:
MyRemoteObjClass obj = (MyRemoteObjClass) Activator.GetObject(typeof(MyRemoteObjClass));
Or
MyRemoteObjClass obj = new MyRemoteObjClass();
QUESTION 2-b-4: Do we need "using XXX.YYYY" in our client application to reference namespace used in remoting object class?
Question 3: Okay, this's a silly question, but what the difference between URI and URL?
RemotingConfiguration.RegisterWellKnownServiceType(typeof(MyRemoteObjClass), "MyRemoteObjURI", WellKnownObjectMode.SingleCall);
What's "MyRemoteObjURI"? I thought a URI is like an URL:
"http://127.0.0.1/MyRemoteObjURI"
Doesnt a URI contains: "protocol alias" + "domain name/IP" + "resources identifier" (which is MyRemoteObjURI" in this case)?
That's a lot of questions, thanks for going over them.
norm
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Hi, just going over some code, came across this:
object[] channelData = or.ChannelInfo.ChannelData;
foreach(object data in channelData)
{
...
ChannelDataStore dataStore = data as ChannelDataStore; //QUESTION: "as" keyword - what does it do?
...
}
I thought in C#, unlike in VB, we don't "as". If we need to cast, we do this:
ChannelDataStore dataStore = (ChannelDataStore) data;
THanks.
norm
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i should not swear on this but i think this is how it works.
if you do
bla var=(bla)some_other_var;
you will get an error if "some_other_var" is null
but if you do:
bla var= some_other_var as bla
it will accept null values to , (i think , ive not tested this but i think i saw that somewhere)
//Roger
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What if data cannot be casted to the type ChannelDataStore? What would happen is there would be an error, and you wouldn't be able to trap the error. So the makers of the C# language included this keyword, so that the variable would become null if casting failed, rather than throwing an error.
"Blessed are the peacemakers, for they shall be called sons of God." - Jesus
"You must be the change you wish to see in the world." - Mahatma Gandhi
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As others have mentioned, casting will throw an error if the cast is invalid. The 'as' keyword will never throw an error - it will return 'null' if the cast is invalid.
MyClass myClass;
object otherObject;
myClass = otherObject as MyClass;
is logically equivalent to the following:
MyClass myClass;
object otherObject;
if( otherObject == null || !typeof(MyClass).IsAssignableFrom(otherObject.GetType()) )
myClass = null;
else
myClass = (MyClass)otherObject;
--
Russell Morris
"So, broccoli, mother says you're good for me... but I'm afraid I'm no good for you!" - Stewy
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That's the best explaination i have seen today. Thanks.
norm
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Does anyone know how to list the content of this folder? I've tried using the System.IO.Directory class to no avail.
God, I pity me! - Phoncible P. Bone
If I end up Windows ME someone is going to be hurting. - One of the answers to a question for What OS are you
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Just a gues, maybe you can do it with System.Managgement. There are some classes for Network in WMI.
Mazy
No sig. available now.
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Thanks. I'll take a look at that now.
God, I pity me! - Phoncible P. Bone
If I end up Windows ME someone is going to be hurting. - One of the answers to a question for What OS are you
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Hi,
Im having issues whit a loop.
When i try to return the function in the loop, it tells me the function has no return value.
[WebMethod]<br />
public string GetBiosInfo(string Username, string Password)<br />
{<br />
ConnectionOptions co = new ConnectionOptions();<br />
co.Username = Username;<br />
co.Password = Password;<br />
ManagementScope ms = new System.Management.ManagementScope("\\\\127.0.0.1\\root\\cimv2", co);<br />
<br />
ObjectQuery oq = new ObjectQuery("SELECT * FROM Win32_BIOS WHERE PrimaryBIOS = TRUE"); <br />
ManagementObjectSearcher query = new ManagementObjectSearcher(ms,oq);<br />
ManagementObjectCollection queryCollection = query.Get();<br />
<br />
foreach(ManagementObject mo in queryCollection) <br />
{<br />
return mo["Name"].ToString();<br />
}<br />
}
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What the compiler is saying, is that "not all code paths return a value". This is because you don't return anything outside the foreach loop.
The problem lies in the fact that it is theoritically possible that the queryCollection is empty. If it is empty you bypass the loop and go directly to the end of the method. Return something after the loop and the problem will go away.
Also, are you sure you only want to execute the loop once? I mean right when you enter the foreach for the first time you will be exiting the method also.
-Nathan
---------------------------
Hmmm... what's a signature?
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I have a C# windows appliation with an Access database. There are 2 tables: USERS and PERMISSION_TYPES. Table definitions are:
Table Name: USERS
Fields:
First_Name
Last_Name
Address
PERMISSION_TYPE (FK to PERMISSION_TYPES)
Table Name: PERMISSION_TYPES
Fields:
PERMISSTION_TYPE (PK)
DESCRIPTION
The tables are linked vis the PERMISSION_TYPE field. I can make successful updates to the database, however, I'm trying to use a datagrid for each table so the user can Insert, Update, and Delete records in each table.
When the PERMISSION_TYPES.DESCRIPTION field is changed, an error message is returned that states:
"The record cannot be deleted or changed because table 'USERS' includes releated records"
This doesn't make any sense to me, since the DESCRIPTION field is not a Primary Key, and the updates are successful within Access. I have used the generated Update code, and I have written my own update code - I get the same error message.
Does anyone know what is wrong?
Thanks so much,
Randy
dorianr@mail.com
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Hi Randy,
dorianr wrote:
This doesn't make any sense to me, since the DESCRIPTION field is not a Primary Key, and the updates are successful within Access. I have used the generated Update code, and I have written my own update code - I get the same error message.
This sounds really a bit strange - just as the line would first be deleted, and later inserted again 
I think PERMISSION_TYPES is just a lookup table. Something that helps
the user of your program to sort the records in the user table. Personally I prefer not to have the user edit a lookup table side by side of the main table.
I do this because:
- the permission type is linked to more than one line, editing with only one row is usually specific, and lookups should be general
- On a multi user system not all users should have adminstrator priviledges, eg access to the options. Defining possible permissiontypes (or more general: options)is the admins task
OK, this does not really solve your problem with the table, but perhaps an other way of doing things might be helpful.
Sascha
--
http://www.livingit.de
http://www.mobile-bookmarks.info
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