function readOnly(count){ }
Sign Up ›
Starting November 20, the site will be set to read-only. On December 4, 2023,
forum discussions will move to the Trailblazer Community.
Learn More

Browse by Topic
ShowAll Questionssorted byDate Posted
+ Start a Discussion
Joe HayesJoe Hayes 

Trigger on Attachment to copy Id to custom object

Hi everyone,

I am fairly new to apex and trigger writing but here goes...

I have a custom object called Course_Sale. Our sales team create new course sale records and then attach an invoice in pdf format. I am trying to create a trigger that will copy the id of the attachment just uploaded to a custom field called AttachmentId__c on the Course Sale object.

This attachment id can then be passed into a custom button which will send an email template with the invoice attachment automatically.

I have started the trigger but I am not confident in writing it, It only needs to run on attachments relating to the course sale object and simply needs to copy the attachment id to attachmentId__c on the custom object.

Please can someone have a look at the code below and tell me where I am going wrong? 
trigger AttachmentIDtoCourseSale on Attachment (after insert) {
    List course_saleList = new List();
    Set course_saleIds = new Set();
    for (Attachment att : trigger.New){
        if(att.ParentId.getSobjectType() == course_sale.SobjectType){
            course_saleIds.add(att.ParentId);
        }
    }
    course_saleList = [select id, from course_sale where id in : course_saleIds];
    if(course_saleList!=null && course_saleList.size()>0{
        course_sale.AttachmentId__c = "att.Id";
    }
       update course_saleList;
}

Thank you for your help,

Kind regards
Joe
Best Answer chosen by Joe Hayes
hitesh90hitesh90
Hello Joe,

Try to use following Code.
Apex Trigger: 
trigger AttachmentIDtoCourseSale on Attachment (after insert) {
    Map<Id, Id> mapCSId = new map<Id, Id>();
    List<Course_Sal__c> lstCSUpdate = new List<Course_Sal__c>();
    String objectName = '';
    for(Attachment atc: trigger.new){
        String myIdPrefix = string.valueOf(atc.ParentId).substring(0,3);
        Map<String, Schema.SObjectType> gd =  Schema.getGlobalDescribe(); 
        for(Schema.SObjectType stype : gd.values()){
            Schema.DescribeSObjectResult r = stype.getDescribe();
            String prefix = r.getKeyPrefix();
            if(prefix!=null && prefix.equals(myIdPrefix)){
                objectName = r.getName();
            }
        }
        if(objectName == 'Course_Sal__c'){
            mapCSId.put(atc.ParentId, atc.id);
        }
    }
    if(!mapCSId.isEmpty()){
        List<Course_Sal__c> lstCourseSal = [select id from Course_Sal__c where id in: mapCSId.keyset()];
        for(Course_Sal__c cs: lstCourseSal){
            cs.AttachmentId__c = mapCSId.get(cs.id);
        }
        if(!lstCourseSal.isEmpty()){
            update lstCourseSal;
        }
    }
}


Let me know if you have any question on this. Please mark this "Solved" if it helps.

Thank You,
Hitesh Patel
Email :- hiteshpatel.aspl@gmail.com
http://mrjavascript.blogspot.in/

All Answers

hitesh90hitesh90
Hello Joe,

Try to use following Code.
Apex Trigger: 
trigger AttachmentIDtoCourseSale on Attachment (after insert) {
    Map<Id, Id> mapCSId = new map<Id, Id>();
    List<Course_Sal__c> lstCSUpdate = new List<Course_Sal__c>();
    String objectName = '';
    for(Attachment atc: trigger.new){
        String myIdPrefix = string.valueOf(atc.ParentId).substring(0,3);
        Map<String, Schema.SObjectType> gd =  Schema.getGlobalDescribe(); 
        for(Schema.SObjectType stype : gd.values()){
            Schema.DescribeSObjectResult r = stype.getDescribe();
            String prefix = r.getKeyPrefix();
            if(prefix!=null && prefix.equals(myIdPrefix)){
                objectName = r.getName();
            }
        }
        if(objectName == 'Course_Sal__c'){
            mapCSId.put(atc.ParentId, atc.id);
        }
    }
    if(!mapCSId.isEmpty()){
        List<Course_Sal__c> lstCourseSal = [select id from Course_Sal__c where id in: mapCSId.keyset()];
        for(Course_Sal__c cs: lstCourseSal){
            cs.AttachmentId__c = mapCSId.get(cs.id);
        }
        if(!lstCourseSal.isEmpty()){
            update lstCourseSal;
        }
    }
}


Let me know if you have any question on this. Please mark this "Solved" if it helps.

Thank You,
Hitesh Patel
Email :- hiteshpatel.aspl@gmail.com
http://mrjavascript.blogspot.in/
This was selected as the best answer
Joe HayesJoe Hayes
Hi Hitesh,

That has worked perfectly! Thank you so much for this. It's a massive relief getting this working.

Thank you
Joe
hitesh90hitesh90
Great..  Welcome Joe!!
Ivan KovacekIvan Kovacek
HI, can you help me with updated versiion that will pull the file ID in same manner as this was pulling AttachmentID? Org has moved to files and every attachment gets automaticly converted to file. 
Thanks