Question

I have domain classes as:

package mnm.schedule 

class Project { 
        static hasMany = [ tasks : Tasks , users : User ] 
        String name 
        static constraints = { 
                name(nullable:false) 
                tasks(nullable:true) 
        } 
}

User.groovy

package mnm.schedule 
import org.example.*; 
class User extends SecUser { 
        //relationships. . . . 
        static belongsTo = [ company : Company, role : Role, resource : Resource] 
        static hasMany = [ holidays : Holiday, tasks : Tasks, pt:String ] 
        Profile profile 
        Project project 
        String username 
        String password 
        boolean enabled 
        List pt 
        boolean ptTaken       
} 

I have a view file, inside which i have this code snippet :

<g:each in="${ans}">
                <li>${it.username.toUpperCase()}<g:checkBox name="checkedUsers" value="${ans}" checked="false" /></li>
</g:each>

The variable ans is the arraylist, that has user objects. I use g:checkBox, so that end user can “check” the required users name.When the user submits this form, I do this action in my controller:

def users = params.checkedUsers 
users.each { index -> 
    new Project(name:"testing",users:index).save() 

    }   

The idea is that I need to add the choose user(via checkbox) to the project.

But this throws the error as :

2012-02-03 10:13:08,173 ["http-bio-8080"-exec-4] ERROR errors.GrailsExceptionResolver  - TypeMismatchException occurred when processing request: [POST] /scheduleNew/project/project - parameters: 
_checkedUsers: 
_checkedUsers: 
Add: Add 
checkedUsers: anto2 
Provided id of the wrong type for class mnm.schedule.User. Expected: class java.lang.Long, got class java.lang.String. Stacktrace follows: 
Message: Provided id of the wrong type for class mnm.schedule.User. Expected: class java.lang.Long, got class java.lang.String

Whats going on? Where I went wrong?

Answer 1

Seems a few things a bit odd to me (but maybe I am not fully understanding what you are trying to achieve).

View:

<g:each in="${ans}">
    <li>${it.username.toUpperCase()}<g:checkBox name="checkedUsers" 
       value="${it.id}" checked="false" /></li>
</g:each>

I would pass the id rather than the entire list (you had value=”${ans})

In the controller, the passed params are of type String, that’s why you are getting the type mismatch. There are several ways to do this, one solution is below:

Controller:

def actionCalled = {
   def project = new Project(name:"testing")       
   def users = params.checkedUsers
   users.each { index -> 
      def user = User.findById(index.toLong())
      project.addToUsers(user)
   }   
   project.save()
}

I’m sure you can simplify this further.