Multiple select value and spring:bind

[fmourioux]

My question is very simple :

how can i use a select with multiple value and spring:bind ?

In fact i have a list of users, every user has N role, and i like to show/choose the list of the role with a select with the property mutiple="true".

					<spring&#58;bind path="utilisateur.roles">
					  <select name="idRoles" multiple="true" >
					    <c&#58;forEach var="role" items="$&#123;roles&#125;">
					    </c&#58;forEach>
					  </select>
						<span class="fieldError">$&#123;status.errorMessage&#125;</span>
					</spring&#58;bind>

Anyone a sample ?

Fabien.

[j2ux]

Below is an excerpt from the mailing list I once used for testing (and it worked!).
You may encounter the problem when working with "multi-select-boxes" that the request only contains the selected items.

Another reference you can check is AppFuse

https://appfuse.dev.java.net/

it contains a multi select box but without using "spring:bind" (but solves the problem of non-selected items).

Regards,
Lars

As this solution not only applies to checkboxes, but also to html <select> fields with multiple values allowed, I would suggest renaming "checkbox" to something else, "field" maybe?

For example:

<spring:bind path="recommendation.involvedMemberStates">
<input type="hidden" name="_checkbox.<c:out
value="${status.expression}"/>">
<select name="<c:out value="${status.expression}"/>" size="6"
multiple>
<c:forEach var="memberState" items="${status.value}">
<option value="<c:out
value="${memberState.memberStateCode}"/>">
<c:out value="${memberState.name}"/>
</option>
</c:forEach>
</select>
</spring:bind>

This renders a 6-line select box where you can select multiple values.
If none are selected, the parameter is not present in the request, and the "_checkbox" hidden field ensures the bean property is set to null.

This works fine, but the "checkbox" naming is a bit undesirable...

Kind regards,
Tom.

[fmourioux]

I'am ok for displaying the selected roles.

But how can i retreive the roles selected in the list box when i submit the form ?

[j2ux]

You can use the request, e.g.:

String[] userRoles = request.getParameterValues("userRoles");
if (userRoles != null) {
for (int i = 0; i < userRoles.length; i++) {
log.debug(userRoles[i]);
}
}

[fmourioux]

Thanks a lot, again !

[uze]

I have problem with the same multi-select context. My model object has a property of type List containing objects binded to a list of checkboxes in a form. Now when I submit the form, what is the proper way to set that List property (ie to rebuild/add the List's property objects based on the form's checked boxes)???

Any help would be appreciated.

Uze

[fmourioux]

Hi uze ! can u send us more information (small peice of your code for example) about your pb in order to solve it ?

Thanks,

Fabien.

[uze]

Ok, I'll try to make it short:

I have a car class with a drivers List property like this:

Class Car{
  public List drivers
  ...
}

Car is the command passed thru formBackingObject() and refererenced as myDataModel in the view:

<spring&#58;bind path="myDataModel.drivers">
	
	<c&#58;forEach var="driver" items="$&#123;allDrivers&#125;">
		<INPUT class="checkbox" type="checkbox"
			name='<c&#58;out value="$&#123;status.expression&#125;.$&#123;driver.id&#125;" />'								
			<c&#58;forEach var="d" items="$&#123;myDataModel.drivers&#125;">								
				<c&#58;if test="$&#123;d.Id==driver.Id&#125;">CHECKED</c&#58;if>								
			</c&#58;forEach>>										
		<c&#58;out value="$&#123;model.modelName&#125;" />
		<br/>
	</c&#58;forEach>
	
</spring&#58;bind>

allDriver being a List of driver passed thru referenceData(). This will generate as much checkboxes as there is driver objects and check the ones that have a matching driver object in myDataModel.

When I post the form, I want myDataModel.drivers (which is a List) to be populated with the checked items only. Now, I could parse manually the request and create the required driver objects, but I am wondering if we can have something like the propertEditors to do the trick.

Any ideas???

Uze

[fmourioux]

I have the same problem, i did it manually in the controller exactly in the onBind part. I don't find an example for propertyEditor for the moment.

I hope someone will help us, for this moment the classic solution works well and it can be upgraded later.

Fabien.

[uze]

Now I really need help. I tried parsing the request in the onBind as Fabien mentionned but Spring trows me

Failed to convert property value of type [java.lang.String] to required type [java.util.List] for property models

with this jsp:

<spring&#58;bind path="reoDataModel.models">
	<c&#58;forEach var="model" items="$&#123;models&#125;">
		<INPUT class="checkbox" type="checkbox"
			value='<c&#58;out value="$&#123;model.programId&#125;" />'
			name='<c&#58;out value="$&#123;status.expression&#125;" />'								
			<c&#58;forEach var="m" items="$&#123;reoDataModel.models&#125;">								
				<c&#58;if test="$&#123;m.programId==model.programId&#125;">CHECKED</c&#58;if>								
			</c&#58;forEach> >								
		<c&#58;out value="$&#123;model.modelName&#125;" />
		<br />
	</c&#58;forEach>
</spring&#58;bind>

And this is the code in my form controller:

	protected void onBind(HttpServletRequest request, Object command, BindException errors) {

			ReoDataModel reo = (ReoDataModel) command;	
			
			//parse checked models from the request 
			List models=new LinkedList();
			String[] reqModels = request.getParameterValues("models");
			if (reqModels != null) {				
				for &#40;int i = 0; i < reqModels.length; i++&#41; &#123;
					models.add&#40;Model.findById&#40;reqModels&#91;i&#93;&#41;&#41;;					
				&#125;	
			&#125;

			reo.setModels&#40;models&#41;;
	&#125;

Do I have to remove the bind from the JSP? How can spring know I've actually handled this property of the command and how can I tell Spring to ignore it?

Any hint would help!

Uze