What is "named content part" and when should we use it?

[aaronamm]

Hello everyone

I just found we have "named content part" in Orchard Core.
I know that Orchard has had content part since a version 1 and it has a class model along with it.

After digging some code, I still don't quite understand the purpose of "named content part" and there it is not mentioned in OrchardCore doc.

Here are what I founds:

• Article name part in blog.recipe.json

              "PartName": "Article",
              "Name": "Article",
              "Settings": {
                "ContentTypePartSettings": {
                  "Position": "3"
                }

• In admin content type definition that we can add a named part
  

My question are:

• Please could you explain what is named part?
• What is the purpose of it?
• I wonder if a problem we have can be solved with a traditional content part.

Thanks.

FYI

I can't figure it out the real different between AddPartToType and AddReusablePartToType in "ContentDefinitionService.cs"

        public void AddPartToType(string partName, string typeName)
        {
            _contentDefinitionManager.AlterTypeDefinition(typeName, typeBuilder => typeBuilder.WithPart(partName));
            _contentDefinitionEventHandlers.Invoke((handler, context) => handler.ContentPartAttached(context), new ContentPartAttachedContext { ContentTypeName = typeName, ContentPartName = partName }, _logger);
        }

        public void AddReusablePartToType(string name, string displayName, string description, string partName, string typeName)
        {
            _contentDefinitionManager.AlterTypeDefinition(typeName, typeBuilder => typeBuilder.WithPart(name, partName, cfg =>
            {
                cfg.WithDisplayName(displayName);
                cfg.WithDescription(description);
            }));

            _contentDefinitionEventHandlers.Invoke((handler, context) => handler.ContentPartAttached(context), new ContentPartAttachedContext { ContentTypeName = typeName, ContentPartName = partName }, _logger);
        }

[jptissot]

I think the difference is that usually you can only attach 1 reference of a part to a content item. But for Named Parts, you can attach X instances, each would have a different names.

For example, the BagPart can be attached multiple times to the same item for different purposes.

[aaronamm]

@jptissot Thank you for your answer. I understand what you explained but I still don't quite understand why we need named part Article in Article content type. Is it possible if you could explain it to me?

Here is how we attach Article named part to Article content type.
https://github.com/OrchardCMS/OrchardCore/blob/dev/src/OrchardCore.Themes/TheBlogTheme/Recipes/blog.recipe.json#L113

Thanks.

[deanmarcussen]

The Article part you are referring to is a special part which contains the fields for the current content type.

It's not exactly a NamedPart, just the part where fields are placed.

NamedParts are by design, parts that be attached to a content type multiple times, with a different name

[aaronamm]

@deanmarcussen Thank you so much.
However, could you help point find the field that Article part store?
I cannot find any "Article.cs" model which differs from AutoroutePart, HtmlBodyPart, TitlePart that ways have xxxPart.cs.

Thanks.

[deanmarcussen]

There is no Model. It's where fields are placed. Dynamically. Through the admin ui.

In the case of Article in that recipe, it has a TextField named Subtitle and MediaField on it

[aaronamm]

@deanmarcussen Thank you for your prompt reply.
Now, I get it.

Here is how we define dynamic Article part, just for reference.

Only defining of Article part in src/OrchardCore.Themes/TheBlogTheme/Recipes/blog.recipe.json.

{
   "ContentParts":[
      {
         "Name":"Article",
         "Settings":{
            
         },
         "ContentPartFieldDefinitionRecords":[
            {
               "FieldName":"TextField",
               "Name":"Subtitle",
               "Settings":{
                  "ContentPartFieldSettings":{
                     "DisplayName":"Subtitle",
                     "Position":"0"
                  }
               }
            },
            {
               "FieldName":"MediaField",
               "Name":"Image",
               "Settings":{
                  "ContentPartFieldSettings":{
                     "DisplayName":"Banner Image",
                     "Position":"0"
                  },
                  "MediaFieldSettings":{
                     "Multiple":false,
                     "AllowAnchors":true
                  }
               }
            }
         ]
      }
   ]
}