form:checkbox --> default checked

[TerpInMD]

Hello,

This should be easy but has taken longer than I wanted it to. All I want to do is have the checkbox default to checked when the form is rendered no matter what values are in the backing list. Suggestions?


I am using <form:checkbox path="theList" value="someValue" />

Thanks,

[blueskies]

I think the only way to get it checked is based on the property of that field in the object. Why don't you want to set the value in the object?

[TerpInMD]

Thanks for the quick reply. I am open to anything. Basically I am using that list to get the ID's (string) of the objects I am going to save...the value is the actual object ID. As I type this I am realizing I will likely need an editor to set and get the values. Seems like a lot to go through to just have the default set to checked instead of not checked.

[blueskies]

I'm also trying to fully understand the Spring tags. It does seem like something simple you want to do ends up difficult to figure out.

[infinity2heaven]

<form:checkbox path="theList"/> will persist the checked value only if theList is of type Boolean/boolean. If your UI has a checkbox, you would most probably have a boolean to represent that in your domain/command objects. If you don't, then revisit your domain model!

If you still want to bind a non-boolean value, then it get's completed. You need to write a custom taglib which generates the value field, something like this

<form:checkbox path="isReadOnly" value="<tags:processReadOnly value="${command.isReadOnly}"/>"/>

processReadOnly is your tag library, where you can write the logic of returning true or false

[TerpInMD]

What I have is a list and I am using a checkbox to select and item from a list:


Object1 PropertyA PropertyB <checkbox here value="Object1Id">
Object2 PropertyA PropertyB <checkbox here value="Object2Id">
Object3 PropertyA PropertyB <checkbox here value="Object3Id">
Object4 PropertyA PropertyB <checkbox here value="Object4Id">

where PropertyA PropertyB are properties of the Objects. The checkbox's are bound to an Array list of Strings. So when the form is submited I only get the values that are selected.

All works well except that I want the checkbox's to default to being selected instead of being deselected.

[Jörg Heinicke]

If your UI has a checkbox, you would most probably have a boolean to represent that in your domain/command objects. If you don't, then revisit your domain model!

I don't agree with that. A bunch of checkboxes is a valid use case for multi-selection. That seems to be what he wants. PropertyEditor is the correct way to go then.

Joerg

[infinity2heaven]

A bunch of checkboxes for multi select is indeed a valid Use Case, I agree Jörg.

It would have been much simpler if the checbox is backed by a boolean value to transfer state (like object1.isSelected) But if it's used for other semantics like being bound to an Id, it gets complicated. You would have to write a Property Editor for the outer Object class type (Cant write for the checkbox itself I think, as it's a string type).

That's just my thought.