Dynamically display helptext in visualforce

Question

In a visualforce page I want to render help text dynamically.

Suppose if some field is blank and the user tries to save the record I want to show that help text.

But I want this to happen only once, the next time when user click the save and that field is empty I don't want the message to render.

Answer 1

You'll need to use a custom controller or a controller extension to do this, and then just use a simple flag to check these fields on save.

// In the controller
private Boolean CheckDone = false;

public PageReference DoSave()
{
  Boolean AllGood = true;

  if(!CheckDone)
  {
    // check the fields in question
    if(SomeRecord.Field__c == '')
    {
      ApexPages.AddPageMessage(new ApexPages.PageMessage(ApexPages.Severity.Info, 'You haven't entered a value for the field Field__c.');
      AllGood = false;
    }
    else if(SomeRecord.OtherField__c == '')
    {
      // etc.
    }
  }

  if(CheckDone || AllGood)
  {
    // Save the record
    upsert SomeRecord;
    CheckDone = false;
    return SomePageReferenceOrNull;
  }

  CheckDone = true;
  return null;
}

In the page you just need to be sure to include a messages tag and to use your custom Save action for the button being used:

<apex:pageMessages/>

<apex:pageBlock>
  <apex:pageBlockButtons>
    <apex:commandButton action="{!DoSave}" value="Save"/>

Note I've written this code in-browser, so can't be sure that it'll compile as is, but I hope it demonstrates the technique effectively.