Error : Loop variable must be of type Id

Question

Can anyone please tell me, what should I do to avoid this error.

Error : Loop variable must be of type Id.

What I am trying to do is,From incident object list and task object list, I am finding out the task which are linked to incident and collecting those task in list of type Id.

                                                                                                                                                                                                                          Below is the code which I have written. As you said to you use map here but for Id will it hold string type?   

    List<Id> t1=new List<Id>();
    for(Integer j=0;j<resolvedIncident.size();j++)
    {
        for(Integer k=0;k<task.size();k++)
        {
            if(resolvedIncident.get(j).Id==task.get(k).BMCServiceDesk__FKIncident__c)
            {

                t1.add(task.get(k).BMCServiceDesk__FKIncident__c);               
                count=t1.size();                    
            }                
        }

        List<BMCServiceDesk__Task__c> T = new List<BMCServiceDesk__Task__c>();
        for(BMCServiceDesk__Task__c updateTask : t1) // @ this line error 
        {
            updateTask.BMCServiceDesk__FKStatus__c = closedStatusID.id;
            T.add(updateTask);

        }  

Please suggest for the same. Thanks!

Answer 1

For iterating through for loop, you must have a List/Set type variable.

Since you've Id in t1 then better use for loop as below:

// Initialize a list of task which needs to be updated
List<BMCServiceDesk__Task__c> lstUpdateTask = new List<BMCServiceDesk__Task__c> ();
for(Integer j=0;j<resolvedIncident.size();j++)
{
    for(Integer k=0;k<task.size();k++)
    {
        if(resolvedIncident.get(j).Id==task.get(k).BMCServiceDesk__FKIncident__c)
        {
            // add matched task into the list which needs to be updated.
            lstUpdateTask.add(task.get(k));                  
        }                
    }
}   

// Now we've list of Task which needs to be updated, simply run a for loop on it
for(BMCServiceDesk__Task__c updateTask : lstUpdateTask) {
    updateTask.BMCServiceDesk__FKStatus__c = closedStatusID.id;
} 

// Once all values are updated, simply update it.
if(lstUpdateTask.size () > 0)
    update lstUpdateTask;

Answer 2

The problem in the loop is that when we are iterating using the below code

for(BMCServiceDesk__Task__c updateTask : t1) // @ this line error 

The system is expecting the the variable t1 should be of type object - BMCServiceDesk__Task__c instead of having a list<id> try to use list<BMCServiceDesk__Task__c>

Hope this answers the questions :)