Getting blank value while using Map

Question

I'm practicing on creating a Trigger (still many things to learn...)

I would like to know on why am I getting a blank value on Text__c, the record's email address is an email address of an exisiting User.

See code snippet below.

trigger AutoChangeOwner on Contact (before insert, before update) {

Set<String> conEmail = new set<String>();
Map<String, Id> UsrMap = new map<String, Id>();

for(Contact con : trigger.new ){
    conEmail.add(con.Email);
    system.debug('conemail' + conEmail);
}

List<User> userEmail = [SELECT Id, Name, Email FROM User WHERE Email != null];
for(User u : userEmail){
    if(conemail.contains(u.email)){
        UsrMap.put(u.Email, u.Id); 
        system.debug('useremail' + userEmail);
    }
}

for(Contact c : trigger.new){
    c.Text__c = UsrMap.get(c.Email);
}

}

Any kind of explanation or ways to enhance the code is much appreciated!

Answer 1

As the comments point out (I can't comment so I cant explain there) You're comparing a String (u.email) and a Set (conemail) these to things cannot be equal as one is a single string and one is a Set of strings. You just need to check if the String is in the Set. You can do this using contains(value) so if you replace if(u.email == conemail) with if(conemail.contains(u.email)) it should solve your problem

Answer 2

You should use system.debug('conemail' + conEmail); after the first loop to see if you're populating the set correctly.

Then check if the list userEmail has been populated correctly with system.debug('useremail' + userEmail);

Answer 3

Your if-statement if(u.email == conemail) will always return false, so your UsrMap will always stay empty.

And doing the .get() on a map with an non-existing key will always return you null.

I would recommend changing that comparison to:

if(conemail.contains(u.email)) {
    // fill in your map here
}