Re: DynamicInvoke a remote object - C# Discussion Boards

Re: Combobox in C# : how to add for each Item a Tag ?

7-Dec-04 13:29

Create a custom object collection where your objects show all the info u need through properties. Then set the collection as ur combo's datasource and set the displaymember and valuemember to your object's properties (Name and Tag for example).

If u dont want to go through all that, it might be easier to just store all objects + info in the necessary fields of a datatable (that would solve ur custom object collection) and proceed the same way as before.

Heath Stewart7-Dec-04 14:47

Re: Combobox in C# : how to add for each Item a Tag ?

7-Dec-04 14:47

For more information and an example of what Skynyrd mentioned, read about the MappingName Property[^] for the DataGridTableStyle class in the .NET Framework SDK.

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Luis Alonso Ramos8-Dec-04 21:24

Luis Alonso Ramos

8-Dec-04 21:24

You can add any object as an item to a ComboBox, and to display it, the ComboBox calls the object's ToString method.

So, create a MyComboItem class that contians two (or more) properties, Text and Tag, and override ToString to return the contents of the Text property. When you get an item from the ComboBox's Items collection, don't forget to do the appropiate cast.

-- LuisR

Luis Alonso Ramos
Intelectix - Chihuahua, Mexico

Not much here: My CP Blog!

DynamicInvoke a remote object

Skynyrd7-Dec-04 12:21

7-Dec-04 12:21

I cant dynamically invoke a method on a remote object. Code is as follows (tested on a dummy class with same method and works perfectly but wont run on the remote object)

public void RunMethod(Type methodType,string methodName,object[] arguments)
{
object proxy=GetProxy (returns a transparent proxy of a singlecall remote object)
Delegate dlg=Delegate.CreateDelegate(methodType,proxy,methodName); throws a System.ArgumentException
dlg.DynamicInvoke(arguments);
}

Is it possible to invoke a remote object through it's proxy this way? If not, how can it be done?

Heath Stewart7-Dec-04 14:48

7-Dec-04 14:48

Please be specific and verbose. What is the message for the ArgumentException? What is the stack trace? Please be sure to also describe the method signature that you're trying to invoke as well.

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Skynyrd8-Dec-04 0:57

8-Dec-04 0:57

Hi Heath,

Sorry, i'm running VS in spanish so I'm not sure how to exactly translate any exception messages without confusing things any more :p

The calling code is as follows:

public delegate string TestMethod();
...
SingleCallManager manager=new SingleCallManager(typeof(IDataLayerTool),"tcp://localhost:8086/DataLayerTool.rem");
manager.RunMethod(typeof(TestMethod),"GetAssetsMenuLayout",null);
...

Complete info on exception is the following: The message would translate to "Error linking to target method." more or less.

[System.ArgumentException]: {"Error al enlazar con el método de destino." }
System.Object: {System.ArgumentException}
_className: null
_COMPlusExceptionCode: -532459699
_exceptionMethod:
_exceptionMethodString: null
_helpURL: null
_HResult: -2147024809
_innerException: { }
_message: "Error al enlazar con el método de destino."
_remoteStackIndex: 0
_remoteStackTraceString: null
_source: null
_stackTrace: {System.Array}
_stackTraceString: " at System.Delegate.InternalCreate(Object target, String method, Boolean ignoreCase)\r\n at System.Delegate.CreateDelegate(Type type, Object target, String method)\r\n at Vigila.Objects.SingleCallManager.RunMethod(Type methodType, String methodName, Object[] arguments) in d:\\proyectos .net\\código aplicaciones\\vigila 2\\vigila objects\\singlecallmanager.cs:line 128\r\n at Vigila.Client.VigilaStartUp.loadUpIniData() in d:\\proyectos .net\\código aplicaciones\\vigila 2\\vigila client\\vigilastartup.cs:line 63\r\n at Vigila.Objects.ThreadWorker.workingEnvelope() in D:\\Proyectos .NET\\Código Aplicaciones\\Vigila 2\\Vigila objects\\ThreadWorker.cs:line 153"
_xcode: -532459699
_xptrs: 0
HelpLink: null
HResult: -2147024809
InnerException: { }
Message: "Error al enlazar con el método de destino."
Source: "mscorlib"
StackTrace: " at System.Delegate.InternalCreate(Object target, String method, Boolean ignoreCase)\r\n at System.Delegate.CreateDelegate(Type type, Object target, String method)\r\n at Vigila.Objects.SingleCallManager.RunMethod(Type methodType, String methodName, Object[] arguments) in d:\\proyectos .net\\código aplicaciones\\vigila 2\\vigila objects\\singlecallmanager.cs:line 128\r\n at Vigila.Client.VigilaStartUp.loadUpIniData() in d:\\proyectos .net\\código aplicaciones\\vigila 2\\vigila client\\vigilastartup.cs:line 63\r\n at Vigila.Objects.ThreadWorker.workingEnvelope() in D:\\Proyectos .NET\\Código Aplicaciones\\Vigila 2\\Vigila objects\\ThreadWorker.cs:line 153"
TargetSite: {System.Reflection.RuntimeMethodInfo}

I repeat, if I implement a non-remote object and try the code, it works perfectly:

public class DummyTest
{
public DummyTest()
{
}

public string GetAssetsMenuLayout()
{
return "Succesful";
}
}

The GetAssetsMenuLayout of the IDataLayerTool has the exact same signature as the dummy class written above but I still cant link to it, and of course the remote object DataLayerTool implements the IDataLayerTool interface. (The transparent proxy getter would fail anyway if that weren't the case)

public interface IDataLayerTool
{
...
string GetAssetsMenuLayout();
...
}

Javier Lozano7-Dec-04 15:02

7-Dec-04 15:02

The MSDN documentation says the following about the function Delegate.CreateDelegate(Type objType,Object target,string method) method.

A System.ArgumentException is thrown when objType does not inherit from either Delegate or MulticastDelegate OR method is not an instance method. http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemdelegateclasscreatedelegatetopic.asp[^]

I'm a little confused about your question: Is it possible to invoke a remote object through it's proxy this way?

When you have a remote objet you use its proxy to call its method exactly the same way you would call other objects. For example, say I have an object called myRemoteObject

<br />
using System;<br />
using System.Runtime.Remoting;<br />
<br />
namespace myRemoteService<br />
{<br />
    // Well Known Web Service object<br />
    public class myRemoteObject : MarshalByRefObject<br />
    {<br />
        // Method myRemoteMethod<br />
        public String myRemoteMethod() <br />
        {<br />
           return "Hello World";<br />
        }<br />
    }<br />
}<br />

You can then call the remote object via it's proxy using the following code:

<br />
using System;<br />
using System.Runtime.Remoting;<br />
using myRemoteService;<br />
<br />
public class Client<br />
{<br />
    static void Main(string[] args)<br />
    {<br />
        //Using a configuration file to have less code...<br />
        String filename = "client.exe.config";<br />
        RemotingConfiguration.Configure(filename);<br />
<br />
        myRemoteObject obj = new myRemoteObject();<br />
        Console.WriteLine(obj.myRemoteMethod());<br />
        obj = null;<br />
<br />
        Console.WriteLine("Done...");<br />
    }<br />
}<br />

This will use a generated proxy to call your method.

Did this help at all?

~javier lozano
(blog)

Skynyrd8-Dec-04 1:08

8-Dec-04 1:08

Hi javier,

thanks for the info.
I can call any method I want of my remote object through its transparent proxy without any problems.

The problem is that I want to localize in one piece of code all the exception handling of the SocketException that gets thrown when the server where the remote object lives is not accessible to the client app that calls one if its methods.

There r two ways around it that I could find right now:

1) Implement the exception handling on all remote calls throughout my code.

2) Create a SingleCallManager object with a generic RunMethod method that will dinamycally link any method calls to the remoteobject (loss of performance is not an issue) dynamically invoking the call to its proxy like you would with any other object. The problem is, that the same piece of code will link perfectly to a dummy non remote class but it will not link to the remote object throwing the exception i've included in the reply to Heath's post. Through this RunMethod method I would be able to localize all excpetion handling of any method call due to a connection failure to the server in one place.

Javier Lozano8-Dec-04 5:07

8-Dec-04 5:07

Hi Skynyrd,

I think I solved your problem or at least came up with an example for you to see. I created a simple remote object with a client and server to host it. Then, I created a delegate so I could call the remote object's method via that delegate. This is what I came up with:

WARNING THIS IS A LONG POST

RemoteObject.cs

using System;

namespace RemoteNamespace
{
	public class RemoteObject : MarshalByRefObject
	{
		public string MyTypeString()
		{
			return this.GetType().ToString();
		}
	}
}

Server.cs

using System;
using System.Runtime.Remoting;


namespace RemoteServer
{

	class Server
	{
		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main(string[] args)
		{
			RemotingConfiguration.Configure("RemoteServer.exe.config");
			Console.WriteLine("Hit <ENTER> to exit.");

			Console.ReadLine();
		}
	}
}

Client.cs

using System;
using System.Runtime.Remoting;
using System.Reflection;
using RemoteNamespace;

namespace RemoteTest
{
	public delegate string del_void();

	class Client
	{
		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main(string[] args)
		{
			RemotingConfiguration.Configure("RemoteTest.exe.config");
			RemoteObject ro = new RemoteObject();

			// To get the list of all methods
			// MethodInfo[] methods = ro.GetType().GetMethods(BindingFlags.Instance | BindingFlags.Public | BindingFlags.InvokeMethod);

			MethodInfo m = ro.GetType().GetMethod("MyTypeString",BindingFlags.Instance | BindingFlags.Public | BindingFlags.InvokeMethod);

			try
			{
				Delegate d = Delegate.CreateDelegate(typeof(del_void),ro,m.Name);
				object o = d.DynamicInvoke(null);
				Console.WriteLine(o);
			}
			catch(TargetInvocationException tie)
			{
				Console.WriteLine(tie.StackTrace);
			}
			catch(Exception e)
			{
				Console.WriteLine(e.StackTrace);
			}
						
			Console.ReadLine();
		}
	}
}

Server.exe.config -- For remoting object config

<configuration>
   <system.runtime.remoting>
      <application>
         <service>
            <wellknown 
               mode="SingleCall" objectUri="RemoteObject.rem"
               type="RemoteNamespace.RemoteObject, RemoteLibrary"/>
         </service>
         <channels>
            <channel ref="tcp" port="8080"/>
         </channels>
      </application>
   </system.runtime.remoting>
</configuration>

Client.exe.config -- For remote object config

<configuration>
   <system.runtime.remoting>
      <application>
         <channels>
            <channel ref="tcp" port="0">
               <clientProviders>
                  <formatter 
                     ref="binary"
                  />
               </clientProviders>
            </channel>
         </channels>
         <client>
            <wellknown 
               url="tcp://localhost:8080/RemoteObject.rem"
               type="RemoteNamespace.RemoteObject, RemoteLibrary"
            />
         </client>
      </application>
   </system.runtime.remoting>
</configuration>

The key for this to work was to use the following line:

MethodInfo m = ro.GetType().GetMethod("MyTypeString",BindingFlags.Instance | BindingFlags.Public | BindingFlags.InvokeMethod);

For some reason when you passed the full name of the method, the object couldn't bind. However, I just tried this, if you pass the name of the method MyTypeString instead of m.Name into the CreateDelegate method, it also works.

Take a look at this code and tell me what you think.

~javier lozano
(blog)

Heath Stewart8-Dec-04 5:58

8-Dec-04 5:58

Skynyrd wrote:
The problem is that I want to localize in one piece of code all the exception handling of the SocketException that gets thrown when the server where the remote object lives is not accessible to the client app that calls one if its methods.

Could you elaborate a little more? No offense, but the grammar is getting in the way of the problem, specifically "thrown when the server where the remote object lives". If I'm correct, you're trying to say that you want to localize the exception message that the server throws, and you want to localize it on the client?

If so, just catch that exception type and display a localized error message to the user, or if this is for a library (never lets your users see exceptions - there's simply no excuse for that in an application, but in a library it's common since your library gets used by applications) localize the text and throw a new exception with the original exception as the InnerException.

Sorry if I'm wrong, but like I said I have problems parsing and understanding your sentance. Again, no offense meant. It's usually not a problem but in this case - in order to hopefully help you with the true problem - I need to be sure I understand you correctly.

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Sustained Engineering
Microsoft

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Javier Lozano8-Dec-04 6:03

8-Dec-04 6:03

using System;

namespace RemoteNamespace
{
	public class RemoteObject : MarshalByRefObject
	{
		public string MyTypeString()
		{
			return this.GetType().ToString();
		}
	}
}

Server.cs

using System;
using System.Runtime.Remoting;


namespace RemoteServer
{

	class Server
	{
		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main(string[] args)
		{
			RemotingConfiguration.Configure("RemoteServer.exe.config");
			Console.WriteLine("Hit <ENTER> to exit.");

			Console.ReadLine();
		}
	}
}

Client.cs

using System;
using System.Runtime.Remoting;
using System.Reflection;
using RemoteNamespace;

namespace RemoteTest
{
	public delegate string del_void();

	class Client
	{
		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main(string[] args)
		{
			RemotingConfiguration.Configure("RemoteTest.exe.config");
			RemoteObject ro = new RemoteObject();

			// To get the list of all methods
			// MethodInfo[] methods = ro.GetType().GetMethods(BindingFlags.Instance | BindingFlags.Public | BindingFlags.InvokeMethod);

			MethodInfo m = ro.GetType().GetMethod("MyTypeString",BindingFlags.Instance | BindingFlags.Public | BindingFlags.InvokeMethod);

			try
			{
				Delegate d = Delegate.CreateDelegate(typeof(del_void),ro,m.Name);
				object o = d.DynamicInvoke(null);
				Console.WriteLine(o);
			}
			catch(TargetInvocationException tie)
			{
				Console.WriteLine(tie.StackTrace);
			}
			catch(Exception e)
			{
				Console.WriteLine(e.StackTrace);
			}
						
			Console.ReadLine();
		}
	}
}

Server.exe.config -- For remoting object config

<configuration>
   <system.runtime.remoting>
      <application>
         <service>
            <wellknown 
               mode="SingleCall" objectUri="RemoteObject.rem"
               type="RemoteNamespace.RemoteObject, RemoteLibrary"/>
         </service>
         <channels>
            <channel ref="tcp" port="8080"/>
         </channels>
      </application>
   </system.runtime.remoting>
</configuration>

Client.exe.config -- For remote object config

<configuration>
   <system.runtime.remoting>
      <application>
         <channels>
            <channel ref="tcp" port="0">
               <clientProviders>
                  <formatter 
                     ref="binary"
                  />
               </clientProviders>
            </channel>
         </channels>
         <client>
            <wellknown 
               url="tcp://localhost:8080/RemoteObject.rem"
               type="RemoteNamespace.RemoteObject, RemoteLibrary"
            />
         </client>
      </application>
   </system.runtime.remoting>
</configuration>

The key for this to work was to use the following line:

MethodInfo m = ro.GetType().GetMethod("MyTypeString",BindingFlags.Instance | BindingFlags.Public | BindingFlags.InvokeMethod);

Skynyrd8-Dec-04 11:26

8-Dec-04 11:26

Javier, thanks a lot for your help. I'm gonna give it a try right now and will let you know how it turns out.

Funny that u can succesfully link if using the mehtodinfo but not through the method's name.

Trying it right away.

Heath, I'm sorry if I'm not explaining myself too well, english isnt my native language :p.

What I'm trying to do is localize all the exception handling of a failed connection to the remote server in one place inside my client app (the singlecallmanager class), and not in all the calls to remote object's different methods throughout my client app code.

Still Javier seems to have solved the problem. Thanks for your time.

Skynyrd8-Dec-04 11:43

8-Dec-04 11:43

Sorry to say but ur code did not work Javier Frown | :(

Still, I've figured out what the problem is. Maybe it was obvious and I've been wasting ur time:

I can't create the proxy using the public interface of my remote object:

object proxy=RemotingServices.Connect(typeof(IDataToolLayer),myUrl.AbsoluteUri);

DynamicInvoke fails.

However, if I create the proxy using the remote object class, everything works ok:

object proxy=RemotingServices.Connect(typeof(DataToolLayer),myUrl.AbsoluteUri);

The question is, is there a way around this? I dont want to have to include the remote library in my client app, it shouldn't be necessary.

Another interesting thing, is that if I try to get the MethodInfo as Javier does in his example, I get a null return if I'm using the IDataLayerTool interface.

Javier Lozano8-Dec-04 12:06

8-Dec-04 12:06

That stinks! Have you seen this article,http://www.thinktecture.com/Resources/RemotingFAQ/USEINTERFACESWITHCONFIGFILES.html[^], from Ingo Rammer?

I've used the code before on a project and it worked great, however I did not call any methods dynamically. I can change my code and see if it will work.

~javier lozano
(blog)

Skynyrd8-Dec-04 13:18

HTML style RichTextBox control

8-Dec-04 13:18

Ok Javier, got it! Big Grin | :-D

I've discoverd one hell of a class in the Reflexion namespace that has solved all my problems: TypeDelegator

public object RunMethod(string methodName, object[] arguments)
{
object proxy=GetProxy();
TypeDelegator delegator=new TypeDelegator(typeof(IDataLayerTool));
return delegator.GetMethod(methodName).Invoke(proxy,arguments);
}

It seems that the TypeDelegator can map correctly through interfaces and even makes the job a lot easier as u dont have to create delegates as u would with a DynamicInvoke.

Nice little class, yessir Big Grin | :-D

Again, thanks for your time Javier.

Beringer7-Dec-04 12:06

Beringer

7-Dec-04 12:06

Does anybody know of a control that behaves like the RichTextBox control of .NET but uses HTML formating instead?

Thanks in advance,
Eric

Re: HTML style RichTextBox control

Beringer7-Dec-04 12:08

Beringer

7-Dec-04 12:08

And I should add that it needs to be Forms based not Web based.
Thanks again
Eric

Re: HTML style RichTextBox control

Heath Stewart7-Dec-04 14:44

7-Dec-04 14:44

The WebBrowser control (what actually is "Internet Explorer") itself does. Customize your toolbox in VS.NET to include the "Microsoft WebBrowser Control" and click OK (this is under the COM tab, not the .NET tab).

Drag and drop that onto your form. That'll create a couple of RCWs (runtime-callable wrappers) that encapsulate the COM control for marshaling to and from managed code. Then add a reference to the Microsoft.mshtml.dll assembly that should've been installed with VS.NET, IIRC.

Cast the AxWebBrowser.Document property to IHTMLDocument2 and set the designMode property to "On" (case-sensitive).

If you google for "WebBrowser designMode" you should find many articles that discuss more advanced interaction and persisting the document.

There's also a lot of commercial controls that extend the capabilities for managed code, like the NetRix HtmlEditor[^] that I evaluated (along with others) and choose for my former employer. It's very good and priced pretty decently. It extends the basic authoring that the WebBrowser control provides with advanced features like tables and more. You can accomplish this all yourself if you read about the hosting interfaces and more for Internet Explorer. Read Programming and Reusing the Browser[^] on MSDN. Knowledge of OLE/COM is very helpful, especially about Interoperating with Unmanaged Code[^].

There are also editors that don't use the WebBrowser control and rely entirely on their own HTML generation and user interaction, like the Writer for .NET[^], from the same guy that wrote .NET Reflector.

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Sustained Engineering
Microsoft

[My Articles] [My Blog]

Sockets and Win2k Issues

Tristan Rhodes7-Dec-04 11:34

Tristan Rhodes

7-Dec-04 11:34

I've found a PING utility online for C#. Looks fine at first glance, and i disected it a bit to see how it worked and tried to run it. However, i get stuck at line 5 of the PingHost method.

When trying to create a socket, it throws an error in the following line:

Socket socket =
new Socket(AddressFamily.AfINet, SocketType.SockRaw, ProtocolType.ProtICMP);

This doesn't work as none of the enumeration members are correct, but I've tried the following, which look to match properly, along with a few dozen other configurations.

socket = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp);

Every time I try and declare the socket though, it throws an error from the windows native API code.

Is this an issue with Win2k?

When I get home, i'll try it with XP and see if that works.

Cheers for the input

Tris

Heath Stewart7-Dec-04 14:27

7-Dec-04 14:27

Whether or not code compiles has nothing to do with the platform on which you're compiling - only with the version of the base class library (BCL) or any other assemblies that you're compiling against.

The AddressFamily.AfiNet member has never been defined for .NET 1.x and is not currently defined for 2.0.

Without the example type and message, however, it's difficult to help you diagnose your problem. Please be specific and verbose about the exception that was thrown.

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Sustained Engineering
Microsoft

[My Articles] [My Blog]

Tristan Rhodes8-Dec-04 0:25

Tristan Rhodes

8-Dec-04 0:25

It's a run time error.

It returns a value of 2 from the native windows API.

Works fine on my XP machine from home.

At work, i'm running Win2k Professional SP3 (Can't upgrade to 4)

As I said, none of the origional enumeration members exist in any of the .net builds. So I tested others.

I even changed the socket type from RAW. Win2k just refuses to construct the socket.

Kinda stumpped on this one.

Cheers

Tris

Daniel Turini7-Dec-04 20:12

Daniel Turini

7-Dec-04 20:12

The Catalyst wrote:
SocketType.Raw
Raw sockets aren't available in Win2k, only in WinXP.
And, IIRC, raw sockets were removed from WinXP SP2.
http://www.interact-sw.co.uk/iangblog/2004/08/12/norawsockets[^]

Yes, even I am blogging now!