object A is child of object opportunity

I want to delete all the child records ie object A when opty stage is closed lost.

Use TRIGGERS

Yes I had done the same step that you had done in your  latest attached document. There might be some issues with process builder thts y i m doing it with triggers but encountering the same probz

 

Still not working i had done the same thing and the error is

 
Workflow Action Failed to Trigger Flow
The record couldn’t be saved because it failed to trigger a flow. A flow trigger failed to execute the flow with version ID 3016F000000QT26. Flow error messages: <b>An unhandled fault has occurred in this… Read more

i want to upload an excel sheet using Vf pages

Yes thats the scenario ...i tried it with Process builder but there was an error of flow...i encountered same error from the trigger

Hi Mohit ,

I am attaching a trigger to count no. of contacts on account (Roll up-action-count)

 

 

Trigger countContacts on Contact (after insert){

Set<Id> accIdset = new Set<Id>();
List<Account> accList = new List<Account>();
List<AggregateResult> arList = new List<AggregateResult>();
Map<String,Double> acmap =… Read more

trigger if account owner changes then related contact owner also change.

Actually i have to deal with all three of them(Account,contact,opportunity) on the same VF page and after selection particular records i want them to get displayed on a new page block

How can i  display records of account, contacts, opty on the same VF page and then process the selected records using wrapper class??

please explain it in detail (the exact working of wrapper class)