This paragraph shows, how to create an EPLAN add-in in C#. To show that installing the .NET framework already provides all necessary tools (C-Sharp compiler etc.), the add-in is not created as a VisualStudio project, but simply using a text editor and the command line tools of the .NET framework. 

a) Getting started: 

Now start your text-editor-of-choice, for instance notepad, and start writing the source. 

b) Creating the module class: 

Every EPLAN add-in, this means also the C# add-in we are going to create, needs a certain class for managing the add-in. This class has to implement the functions, declared by the IEplAddIn interface: 

public class AddInModule: Eplan.EplApi.ApplicationFramework.IEplAddIn
       {
            public bool OnRegister(ref System.Boolean bLoadOnStart)
            {
                  bLoadOnStart=true;
                  return true;
             }
            public bool OnUnregister()
            {
                  return true;
            }
            public bool OnInit()
            {
                  return true;
            }
            public bool OnInitGui()
            {
                  return true;
            }
            public bool OnExit()
            {
                  return true;
            }
      }

Now save this source code in folder SimpleCSharpAddIn as a file named AddInModule.cs. 

c) Compiling the assembly (dll) 

Now's the time for using the C-Sharp compiler. The compiler is located in the directory of the .NET framework, for example. C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727. This folder should be in the search path. Open your favored shell and change to the directory SimpleCSharpAddInwhere you just stored AddInModul.cs . 

Invoke the C-Sharp compiler (csc.exe) with the following parameters: 

csc /target:library /reference:..\..\..\..\bin\Eplan.EplApi.AFu.dll /out: EPLAN.EplAddin.SimpleCSharp.dll AddinModule.cs 

What's the meaning of these parameters? 

1. /taget:library: We want to create a dll and no exe file.
2. /reference:..\..\..\..\bin\Eplan.EplApi.AFu.dll : search in Eplan.EplApi.AFu.dll for all missing data (e.g.. IEplAddIn)
3. /out: EPLAN.EplAddin.SimpleCSharp.dll : name of the dll to build is EPLAN.EplAddin.SimpleCSharp.dll
4. AddinModul.cs: name of the source file to compile

If nothing went wrong with the compilation, you'll now find the dll EPLAN.EplAddin.SimpleCSharp.dll in the folder SimpleCSharpAddIn. Copy this file to the EPLAN bin folder. 

d) Loading an Add-In in EPLAN 

Start EPLAN now. If the following system extensions are loaded in EPLAN (which normally should be the case): EplanEplApiModuleu.erx, EplanEplApiModuleGUIu.erx, you will find “API” and "Manage" under the ribbon item "File", under "Extras", "Interfaces".

After clicking on "Manage", a dialog -- as shown below -- will appear. After pressing the button "Load" you can select Eplan.EplAddin.SimpleCSharp.dll from the bin directory. 

Our add-in now appears in the list of the API modules dialog and will be loaded, when EPLAN is started.That's about all it can do. What we need now is Action! 

e) Adding an Action to the C-Sharp add-in 

Therefore create a second source file and save it as SimpleCSharpAction.cs in your source directory. To create an action, we need a class, which implements the IEplAction interface. For a more detailed explanation, see the Actions topic. 

using Eplan.EplApi.ApplicationFramework;
public class CSharpAction: IEplAction
{
      public bool Execute(ActionCallingContext ctx )
      {
            new Decider().Decide(EnumDecisionType.eOkDecision, "CSharpAction was called!", "", EnumDecisionReturn.eOK, EnumDecisionReturn.eOK);
            return true;
      }
      public bool OnRegister(ref string Name, ref int Ordinal)
      {
            Name  = "CSharpAction";
            Ordinal     = 20;
            return true;
      }
      public  void GetActionProperties(ref ActionProperties actionProperties)
      {
           actionProperties.Description= "Action test with parameters.";
      }
}

Now the compiler call needs to be slightly extended: 

csc /target:library /reference:..\..\..\..\bin\Eplan.EplApi.AFu.dll /reference:..\..\..\..\bin\Eplan.EplApi.Baseu.dll /out:SimpleCSharpAddIn.dll AddinModule.cs SimpleCSharpAction.cs 

If you added an action to an already loaded add-in, the add-in needs to be unloaded and loaded again for the changes to take effect. 

So you just open the "API modules" dialog again, select the add-in in the list and click the "Unload" button. Then load the add-in again. 

Now you can call your new action in EPLAN via a Command line call: 

W3u.exe CSharpAction 

When you start the action, the Execute() function of the CSharpAction is called. This function just shows a MessageBox with the text "CSharpAction was called!". (new Decider().Decide(EnumDecisionType.eOkDecision, "CSharpAction was called!", "", EnumDecisionReturn.eOK, EnumDecisionReturn.eOK);).