Tapestry5 Dialog Avoiding Nested Forms

BlockContainer.java

public interface BlockContainer {
   void addBlock(Block block);
}

Dialog.java

public class Dialog {
   @Environmental
   private BlockContainer blockContainer;
   
   @Inject
   private ComponentResources componentResources;
   
   @Inject
   private Block mainBlock;
   
   public void setupRender() {
     blockContainer.addBlock(mainBlock);
   }
   
   public boolean beforeRenderBody() {
     // don't render body, this will be done in the layout
     return false;
   }
}

Dialog.tml

<t:block t:id="mainBlock">
   <t:form>
      <!-- render the fields in the dialog body -->
      <t:body />
   </t:form>
</t:block>

Layout.java

public class Layout {
   @Inject
   private Environment environment;
   
   @Inject
   private TypeCoercer typeCoercer;
   
   private List<Block> blocks;
   
   public void setupRender() {
      blocks = new ArrayList<Block>();
      environment.push(BlockContainer.class, new BlockContainer() {
         public void addBlock(Block block) {
            blocks.add(block);
         }
      });
   }
   
   public RenderCommand afterRenderBody() {
      environment.pop(BlockContainer.class);
      RenderCommand command = new RenderCommand() {
         public void render(MarkupWriter writer, RenderQueue queue) {
            for (Block block : blocks) {
               RenderCommand subCommand = typeCoercer.coerce(block, RenderCommand.class);
               subCommand.render(writer, queue);
            }
         }
      };
      return command;
   }
}

Usage.tml

<t:form>
   Main Form Field 1: <t:textfield ... />
   Main Form Field 2: <t:select ... />
   
   <t:dialog>
      Dialog Field 1: <t:textfield ... />
      Dialog Field 2: <t:textfield ... />
   </t:dialog>
</t:form>