Accessing a list of params in controller

checkboxgrailsgroovyparametersrequest

Im very new to grails (1.3.7) so please be patient 🙂

I have a gsp where I have various checkboxes. A user can click on them and then send his answer to a controller. The controller is receiving this request correctly.

My problem is, that, for working with what the user chose, I have to check every parameter – to see if this checkbox was really checked. Thats really cumbersome and doesnt work very well, because the page displaying the checkboxes is dynamic – so the checkboxes which can be clicked are dynamic too. In my controller I dont know for which params I have to check then.

Is there any possibility to receive a list of all checkboxes (or better: all checked checkboxes) in my controller? I researched but didnt find an answer!

Thanks for answering! 🙂

[EDIT]

Thank you,

params.name.each{i->
            System.out.println(i);
}

is very simple and works 🙂 It just gives back the checked ones

Best Answer

It must be passed as an extra request parameter (it's a limitation of http). You can add following field into your form, for example:

<input type="hidden" name="checkboxes" value="${myCheckboxesNames.join(',')}"/>

or making same using JavaScript, as it names are dynamic on client side.

BTW, you can also check all request parameters, by

params.each { name, value ->
// so something
}

so if you are using some special prefix/suffix for this checkbox names, it would be:

params.entrySet().findAll {
   it.key.startsWith(prefix)
}.each {
   println "Checkbox $it.key = $it.value"
}

Related Solutions

Asp.net-mvc – How to handle checkboxes in ASP.NET MVC forms

Html.CheckBox is doing something weird - if you view source on the resulting page, you'll see there's an <input type="hidden" /> being generated alongside each checkbox, which explains the "true false" values you're seeing for each form element.

Try this, which definitely works on ASP.NET MVC Beta because I've just tried it.

Put this in the view instead of using Html.CheckBox():

<% using (Html.BeginForm("ShowData", "Home")) {  %>
  <% foreach (var o in ViewData.Model) { %>
    <input type="checkbox" name="selectedObjects" value="<%=o.Id%>">
    <%= o.Name %>
  <%}%>
  <input type="submit" value="Submit" />
<%}%>

Your checkboxes are all called selectedObjects, and the value of each checkbox is the GUID of the corresponding object.

Then post to the following controller action (or something similar that does something useful instead of Response.Write())

public ActionResult ShowData(Guid[] selectedObjects) {
    foreach (Guid guid in selectedObjects) {
        Response.Write(guid.ToString());
    }
    Response.End();
    return (new EmptyResult());
}

This example will just write the GUIDs of the boxes you checked; ASP.NET MVC maps the GUID values of the selected checkboxes into the Guid[] selectedObjects parameter for you, and even parses the strings from the Request.Form collection into instantied GUID objects, which I think is rather nice.

Request variables in grails

The params object is only useful for getting values from the query string of the current request. Setting a value in params in a GSP won't do anything. Params is a request scope object, with each new request it is an entirely new object. To pass a value from your GSP to your List controller, that value must be in the query string of the new request to the controller. In your case, it looks like you want to put it in your "More" link. The way your remoteLink tag is written, the value of nxtPage should be in params.id in your List controller, so you could access it that way. If you want to be in params.pagecount you would have to put it in the params attribute of you remoteLink tag. Something like this:

<g:remoteLink action="list" params="[pagecount: nxtPage]">More</g:remoteLink>

Best Answer

Related Solutions

Asp.net-mvc – How to handle checkboxes in ASP.NET MVC forms

Request variables in grails

Related Topic