Developing and running a sample client

This section describes how to develop and run a .NET C# client application that communicates with an EAServer EJB component.

Creating and deploying an EJB

Create an EJB called EchoEJB and add it to EchoEJB.jar.
To deploy the EJB, run:
```
deploy.bat EchoEJB.jar
```

Generating the C# stubs

Verify that the C# compiler (csc.exe) is in your path.
Run NetCompiler:
```
netcc.bat ejbjar-echoejb
```

NetCompiler creates these C# source files in %DJC_HOME%\genfiles\cs\src:

echoejb.cs – interface file, which must be included to call the EJB.
echoejb_Stub.cs – stub file.
echoejbHelper.cs – helper classes for data marshalling and narrowing.

The source files are packaged in the output assembly %DJC_HOME%\deploy\assemblies\echoejb.client.dll.

You can use the C# stubs that are compiled into assembly files from Visual Basic .NET clients.

Developing the C# sample client

Create a C# file called EchoClient.cs, and add this code:

using System;
using System.Data;
using System.Collections;
using System.Net;
using System.Net.Sockets;

using com.sybase.ejb.net;
using com.sybase.net;

public class EchoClient
{
   public static void Main()
   {
      EjbProvider ejbProvider = EjbProvider.GetInstance();
      ejbProvider.SetProviderURL("iiop://host:port");
      ejbProvider.SetUsername("admin@system");
      ejbProvider.SetPassword("sybase123");

      EjbConnection ejb = EjbConnection.GetInstance();
      EchoRemoteHome home = (EchoRemoteHome)
          ejb.LookupHome(typeof(EchoRemoteHome), "EchoEJB/EchoBean");
      EchoRemote echo = home.create();
      Console.WriteLine( echo.hello("World") );
   }
}

where:

Code	Description
`using com.sybase.net`	Imports the stub classes that were generated by running netcc.bat.
`EjbProvider`	Acts as a name service. The code defines the URL (machine name and IIOP port number), user name, and password.
`ejb.LookupHome`	Gets the home interface com.sybase.net.EchoRemoteHome, looks up the server’s naming context, and gets a stub from the server using the connection information from EjbProvider. The code for EjbProvider and EjbConnection is in com.sybase.ejb.net.dll.
`home.create`	Gets the remote interface com.sybase.net.EchoRemote.
`echo.hello`	Calls the remote interface business method hello.

Compiling and running the C# sample client

To compile EchoClient.cs, run:
```
csc EchoClient.cs /r:%DJC_HOME%\lib\com.sybase.iiop.net.dll /r:%DJC_HOME%\lib\com.sybase.ejb.net.dll /r:%DJC_HOME%\deploy\assemblies\echoejb.client.dll
```
Compiling the client creates EchoClient.exe, which you can run from the command line.

com.sybase.iiop.net.dll and com.sybase.ejb.net.dll are shipped with EAServer 6.1 in the lib subdirectory, and are the basic framework of the .NET client runtime support. echoejb.client.dll is created by netcc.bat when you generate the C# stubs for the EJB. The classes in echoejb.client.dll call methods in com.sybase.iiop.net.dll and com.sybase.ejb.net.dll.
Run:
```
EchoClient.exe
```
The program output is:
```
Hello World!
```

Troubleshooting

If you see the following error message when you run the client application, the necessary assembly files cannot be found:
```
Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'com.sybase.ejb.net, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. File name: 'com.sybase.ejb.net, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' at EchoClient.Main()
```
To solve this problem, you can either:
- Copy the assembly files to the current directory, or
- Create an XML configuration file to identify the location of the assembly files:
  1. In the directory that contains EchoClient.exe, create an XML file called EchoClient.exe.config, and add this code:
```
<?xml version="1.0" encoding="utf-8"?>
<configuration>
 <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
    <probing privatePath="lib"/>
   </assemblyBinding>
 </runtime>
</configuration>
```
  2. Copy these assembly files to the location identified by privatePath, which must be a subdirectory of the application’s base directory:
    - com.sybase.iiop.net.dll
    - com.sybase.ejb.net.dll
    - com.sybase.jms.net.dll