Set General Field on a Component to specific word when the Component is saved

Question

I want to set a General Field (Simple Text Field) on a Component to specific word (ex. "aaa") when the Component is saved, by using Event System.

I success to do the above, but I have one problem.

If the General Field is not Mandatory, it's no problem.

But if the General Field is Mandatory, it's problem, that is, the component isn't saved because of displaying error message "Mandatory field "xxx" is missing a value".

One solution is I set the General Field to not Mandatory.

But I want to set the General Field to Mandatory.

So please tell me a solution, that is,

how to set a General Field to specific word before SDL Tridion check whether the General Field is missing a value or not, using event system.

UPDATE2

the below code is my code.

    private void Subscribe()
    {
        EventSubscription subScription = EventSystem.Subscribe<Component, SaveEventArgs>(copys, EventPhases.Initiated);
        _subScriptions.Add(subScription);
    }

    private void copys(Component component, SaveEventArgs args, EventPhases phases)
    {
        if (!component.Schema.Title.Equals("copy_test")) return;

        ItemFields generalFields = new ItemFields(component.Content, component.Schema);

        foreach (ItemField child in generalFields) 
        {
            if (child.Name=="copy") 
            {
                TextField text = (TextField)child;
                text.Value = "set the value";
            }
        }
        component.Content = generalFields.ToXml();
    }

Answer 1

It sounds like you are hooking into the Processed (or later) phase of the Save operation, which will only be called after the save has happened.

You should instead hook into the Initiated phase of the save. This one occurs before the save and so giving the field a value will satisfy the mandatory requirement of the field when the save does occur.

Update: I feel kind of silly for not noticing this before, but this will never work in the CME, if the field is mandatory. It's not a problem with your event handler: the CME also does client-side validation and that is what is preventing your save in the first place.

Answer 2

Perhaps you can do this through a GUI extension - and thus better inform a user that a value was entered. I presume you're aware that fields can have 'default' values already - which may negate your code even running in many instances?

The best way to approach this (event system, GUI extensions, user process/education) will likely depend on the specifics of 'why' you want populate something, just a couple of quick questions that spring to mind are - are you writing the value irrespective of the user entry (if so, then perhaps this should be a read-only field [read a.n.other GUI extension]) - are you wanting to inform the user they entered something invalid / null

Rob has a nice example of this here and there's a good discussion of the different options from Nuno

Answer 3

Though I am not sure, but I doubt the objects (Components etc.) will restore their values across events. I suspect in the code above, you may need to call the Component.Save method explicitly once you change the content value of the component - After this statement:

component.Content = generalFields.ToXml();

try putting the

component.Save();

and check.