How do I create a data validation function to print the values of a specified column across all pages?

Question

I have a specific task that I believe might require some kind of custom script.

Here is (a copy) of the spreadsheet in question: https://docs.google.com/spreadsheets/d/1fwk-I3VHIeQP4AC4J-vQB8vbuM3YONgCfTTSrDSNhz8/edit#gid=850165930

This spreadsheet is a template for designing the content model of a piece of software. As such, users will be copying the Sheet entitled "---" depending on the configuration of their project.

My question refers to Column C across all of these pages, entitled "Bound Values". I need some way for all variables within this column (across all pages) to be printed within a single column on a hidden sheet (represented by the sheet titled "🌴").

End Goal

Whenever editing cells in the "Bound Values" column, I would like to have the option of selecting previously used variables within this column across other pages.

I can currently only do this by referencing a single, static sheet that I would need to manually update (which is time consuming).

---

Another way of looking at it

I would use this on the hidden sheet to scrape all cell values across all pages in column C:

.

My Questions Are:

• How might one be able to do this in Google Sheets, if at all?
• If not, how might a script be structured to achieve this?

Answer 1

If the names of sheets were known, you'd be able to do something like

={filter(Sheet1!C2:C, len(Sheet1!C2:C)); filter(Sheet2!C2:C, len(Sheet2!C2:C)); ... }

to join all of those together.

But since new Sheets will be added, and you don't know what names they will have, you need a script. I can think of two approaches: (a) the script will collect the data from C-columns itself; (b) the script will update the formula (of the above form) that will do the rest. The second one seems easier to code so I'll go with that.

function updateFormula(e) {
  if (e.changeType === 'INSERT_GRID' || e.changeType === 'REMOVE_GRID') {
    var sheets = e.source.getSheets();
    var formulaBits = [];
    for (var i = 0; i < sheets.length; i++) {
      if (sheets[i].getSheetName() !== '🌴') {
        var quotedName = "'"+sheets[i].getSheetName()+"'";
        formulaBits.push('iferror(filter('+quotedName+'!C2:C, len('+quotedName+'!C2:C)))');
      }
    }
    var formula = '={'+formulaBits.join('; ')+'}';
    e.source.getSheetByName('🌴').getRange('C1').setFormula(formula);
  }
}

To deploy:

1. Open Tools > Script Editor and put the above code there. Click Save.
2. Go to Resources > "This project's triggers" and create a trigger with parameters "from spreadsheet", "on change".

You may want to add a sheet yourself to make the script run the first time; after that it will update the formula in cell C1 of sheet 🌴 whenever a new sheet is added or a sheet is removed.

In case of renamed sheets, the software takes care of renaming itself, adjusting the formula automatically.