Drag and Drop - Limit new items in container

Submitted by warriorofdreams on Mon, 08/18/2008 - 16:07.

[editor: moving to the appropriate forum…]

Today I was experimenting with the Drag and Drop functionality and I need some help. I have one container with some items and about 14 other containers without items (all with the dojotype: dojo.dnd.Source).

Now I want to limit the items in the 14 containers to 1, so that only 1 item can be placed in that container. If there is already a item in the container the user should move that first.

I've searched the forums and the tutorials but I couldn't find a way.
Hopefully someone can help me. Thanks in advance.

Wouter

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It is easy...

Submitted by eugene on Tue, 08/19/2008 - 03:43.

It is easy to do:

Specify "singular: true" either in the source's parameters or in the markup. You don't want your users moving more than 1 element.
Override (either subclass, or monkey-patch) checkAcceptance() method to return "false" if the target is not empty (has 1 element) and it is not the original source (you want to accept own items). Otherwise run the original method. To check how many items you have, use getAllNodes().length.

That worked exactly as I

Submitted by warriorofdreams on Tue, 08/19/2008 - 19:32.

That worked exactly as I wanted! You even found another thing that would give a problem (multiple item selection). Thanks alot!

Just 5 minuts after posting this reply, I found a nother problem: I can't move items back in to the original source because it contains multiple items. Is there someway to see what id the new target has?

Simple solution

Submitted by eugene on Tue, 08/19/2008 - 21:21.

Do not modify the original source, just make it "singular: true". And make sure that your item types and all source/target types match (they do by default).

You can find out the id of a container by inspecting the "node" attribute of a source.

I do not really understand

Submitted by warriorofdreams on Thu, 08/21/2008 - 09:57.

I do not really understand what you are meaning with that. Each item should be able to be placed in every source so working with types will not work.

Nevertheless I've found a solution by giving the original sources a jsID:

if(this == source){ return true; }
		
else if(this != regiment_container_1 && this != regiment_container_2)
{
	if(this.getAllNodes().length > 0)
	{
		return false;
	}
}

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