S9 Basics: Creating a POU

Simply take a look the following code snippet to understand the basic idea:

IPOUObject pouObj = (IPOUObject)ComponentManager.Singleton.CreateInstance(GUID_POUOBJECT);
IImplementationObject implObj = (IImplementationObject)ComponentManager.Singleton.CreateInstance(GUID_STIMPLEMENTATIONOBJECT);
pouObj.Implementation = implObj;
if (pouObj.Interface is ITextVarDeclObject)
   ((ITextVarDeclObject)pouObj.Interface).TextDocument.Text = "PROGRAM MyFirstProgram\nVAR\nEND_VAR";
SystemInstances.ObjectMgr.AddObject(SystemInstances.Engine.Projects.PrimaryProject.Handle, Guid.Empty, Guid.NewGuid(), pouObj, "MyFirstProgram", -1);

Notes

  • POUs with implementation languages other than ST are created the same way. Just replace the GUID_STIMPLEMENTATIONOBJECT value by the type GUID of another implementation language. The typelist file shipped with the Automation Platform SDK will contain the necessary information.
  • Objects other than POU are created the same way. Just replace the GUID_POUOBJECT value by the type GUID of another object type. Depending on the type, setting an implementation or editing the interface is obviously not available. Again, take a look at the typelist file for the GUIDs.
  • You might wonder why we create the objects directly via the Component Manager instead of using instances of the _3S.CoDeSys.Core.Objects.IObjectFactory interface. The reason is that object factories are only used for the "Add Object" dialog in CoDeSys where we must display the object's initialization dialog. The factories should not be used when objects are created programmatically. Exception: Device objects must be created using the device object factory. This is kind of a break in the concept, but once you are aware of it, it should not be a problem at all.