CheckboxGridValidationBuilder

A DataValidationBuilder for a `https://developers.google.com/apps-script/reference/forms/checkbox-grid-validation`.

```javascript
// Add a checkbox grid item to a form and restrict it to one response per
// column.
const form = FormApp.openById('123abc');
const checkboxGridItem = form.addCheckboxGridItem();
checkboxGridItem.setTitle('Where did you celebrate New Years?')
    .setRows(['New York', 'San Francisco', 'London'])
    .setColumns(['2014', '2015', '2016', '2017']);
const checkboxGridValidation = FormApp.createcheckboxGridValidation()
                                   .setHelpText('Select one item per column.')
                                   .requireLimitOneResponsePerColumn()
                                   .build();
checkboxGridItem.setValidation(checkboxGridValidation);
```

### Methods

| Method | Return type | Brief description |
|---|---|---|
| `https://developers.google.com/apps-script/reference/forms/checkbox-grid-validation-builder#requireLimitOneResponsePerColumn()` | `https://developers.google.com/apps-script/reference/forms/checkbox-grid-validation-builder#` | Requires limit of one response per column for a grid item. |

## Detailed documentation

### `requireLimitOneResponsePerColumn()`

Requires limit of one response per column for a grid item.

#### Return


`https://developers.google.com/apps-script/reference/forms/checkbox-grid-validation-builder#` --- this validation builder, for chaining