Question

I am trying to load a value into a field on a view from the action on a controller. How do I reference the specific field I want to load? In .NET it would be something like: in the button click event, this.txtName.Text = “John”. I don’t understand how to do that from a controller and specifically how to reference the view field. I have tried using the params object but it is coming null. I know I am getting to the action based on println statements that I have used.

Here are the relevant code snippets:

from the view:

<td valign="top" class="value ${hasErrors(bean: planetInstance, field: 'name', 'errors')}">
  <g:textField name="name" value="${planetInstance?.name}"/>
</td>
<td class="load">
  <g:actionSubmit value="Load" action="nameLoad"/>
</td>

from the controller:

def nameLoad = {
    // I want to reference and load the "name" textField from the view
}

Any help would be appreciated.

Answer 1

I cannot tell from your code, but you may have forgotten to map the variable name in your controller action nameLoad:

class YourController{    
    def nameLoad = {
        def name = Planet.get(params.id).name //This can be whatever you need it to be to get the correct value assigned to the "name" variable.  Here I assume you have a domain class called "Planet" which may or may not be the case.
        return [name:name] //This is where you map key/value pairs.  The name of the key is what you will type to access the value in your view.  The value is the name of the variable you are dealing with, in this case "name".
    }
}

With the way the code above is set up Grails will assume there is a view called nameLoad in the folder YourController. So the URL will be something like:

http://localhost:8080/yourapp/yourcontroller/nameload

In that view you will access name like this:

${name}

Which could be used in any number of tags, like the <g:select> tag for instance:

<g:select from="${name}" />