How do I save a composite field value in Grails GSP?

问题

I have a composite domain object as follows:

class Person 
{
    static embedded = ['forSale']
    Boolean isSelling
    House forSale
}

class House 
{
    Integer numBedrooms
}

I have a select control for the numBedrooms as follows:

<tr class="prop">
 <td valign="top" class="name">
   <label for="numBedrooms"><g:message code="person.numBedrooms.label" default="Num Bedrooms" /></label>
 </td>
 <td valign="top" class="value ${hasErrors(bean: personInstance, field: 'forSale.numBedrooms', 'errors')}">
     <g:select name="numBedrooms" value="${fieldValue(bean: personInstance, field: 'forSale.numBedrooms')}" 
          noSelection="${['null':'Select a number...']}"
      from="${1..6}"
     />
 </td>
</tr>

Notice that I am using forSale.numBedrooms in the fieldValue on the select. I haven't been able to produce scaffolded code for this to take a look at how it is supposed to be done because the create view which gets generated by create-views contains no references to the fields in the forSale House object.

I also haven't been able to turn up any exampes of composite fields being accessed via GSP, so this is a bit of a guess. In any case the GSP page renders without errors, although that may be because I haven't been able to save any data.

I send the value of numBedrooms back as part of a URl query string...

&numBedrooms=2

When I do this the save code in my controller is failing silently - at least nothing ever gets written to the database. I have switched on debug logging for pretty much everything but I get no messages in the log which suggest anything is wrong, although something obviously is.

If I remove the numBedrooms parameter from the query string then my save proceeds as normal, so I am guessing it is something to do with resolving numBedrooms.

Any clue what I am doing wrong and what I can do to track down my problem?

回答1:

What I do is generate-all for the House Domain then copy and paste the GSP code and remove the files once I am done. I have also found it smarter to create templates to edit the House domain in the case where I am using the House domain later on.

For you GSP you need something like this (Notice the name attribute)

<tr class="prop">
 <td valign="top" class="name">
   <label for="forSale.numBedrooms"><g:message code="house.numBedrooms.label" default="Num Bedrooms" /></label>
 </td>
 <td valign="top" class="value ${hasErrors(bean: personInstance.forSale, field: 'numBedrooms', 'errors')}">
     <g:select name="forSale.numBedrooms" value="${fieldValue(bean: personInstance.forSale, field: 'numBedrooms')}" 
          noSelection="${['null':'Select a number...']}"
      from="${1..6}"
     />
 </td>
</tr>

In your param string you need *forSale*.numBedrooms=2. this code will work with person.properties = params or new Person(params).

The embedded "instruction" only tells Hibernate to include the parameters in the same table they are still seperate Domain classes. It will probably generate a table for the domain even though you may never use it.

Hope this helps.

来源：https://stackoverflow.com/questions/2123871/how-do-i-save-a-composite-field-value-in-grails-gsp

标签

grails

composite

gsp