Problem with ECL files also being expandable in CM explorer, showing publications

Question

In our custom ECL extension, we ran into the following problem. We created an ECL extension that allowed us to browse folders and files in an external system.

The folders and subfolders are showing up fine, and files can also be opened correctly. However, we did notice that the files were also appearing in the tree in the Content Manager Explorer, and were also expandable.

When expanding these items, strangely enough, we would see a list of our publications (see screenshot).

Our ECL extension was based on one of the example implementations we found, but t here, this problem would not occur.

Answer 1

After some debugging, we found the cause of this problem. In our ECL extension, we have to implement the function

public IFolderContent GetFolderContent(IEclUri parentFolderUri, int pageIndex, EclItemTypes itemTypes)
{
  //implementation here
}

The key to the solution is the itemTypes parameter

This ItemTypes parameter contains a list of itemType Enums that you should return. Usually, this is "Mountpoint and Folder" or "Folder and "File". In our initial implementation, we would always return a set of folders, subfolders and files. However, we had to implement the following logic :

//UPDATED code after comment
if (itemTypes.HasFlag(EclItemTypes.File) && itemTypes.HasFlag(EclItemTypes.Folder))
{
   //return both (sub)folders and files. 
}
else if(itemTypes.HasFlag(EclItemTypes.Folder))
{
   //only return (sub)folders
}