Fix saving of CheckboxSetMultivalueField

Fixes #73

src/Fields/MultiValueCheckboxField.php

@@ -208,6 +208,25 @@ public function saveInto(DataObjectInterface $record)
         }
     }
 
+    /**
+     * Load the value from the dataobject into this field
+     *
+     * @param DataObject|DataObjectInterface $record
+     */
+    public function loadFrom(DataObjectInterface $record)
+    {
+        $fieldName = $this->getName();
+        if (empty($fieldName) || empty($record)) {
+            return;
+        }
+
+        if ($record->hasField($fieldName)) {
+            $value = $record->$fieldName;
+
+            parent::setValue($value);
+        }
+    }
+
     /**
      * Return the CheckboxSetField value as a string
      * selected item keys.

tests/MultiValueCheckboxFieldTest.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace Symbiote\MultiValueField\Tests;
+
+use SilverStripe\Dev\SapphireTest;
+use Symbiote\MultiValueField\Fields\MultiValueCheckboxField;
+
+class MultiValueCheckboxFieldTest extends SapphireTest
+{
+    protected static $extra_dataobjects = [
+        MultiValueFieldTest_DataObject::class
+    ];
+
+    public function testLoadFrom()
+    {
+        $obj = new MultiValueFieldTest_DataObject();
+        $obj->MVField = ['One', 'Two'];
+        $field = new MultiValueCheckboxField('MVField', 'MVField', ['One', 'Two', 'Three', 'Four']);
+        $field->loadFrom($obj);
+        $this->assertEquals('One,Two', $field->dataValue());
+    }
+
+    public function testSetValue()
+    {
+        $field = new MultiValueCheckboxField('MVField', 'MVField', ['One', 'Two', 'Three', 'Four']);
+        $field->setValue(['One', 'Two']);
+        $this->assertEquals('One,Two', $field->dataValue());
+        $obj = new MultiValueFieldTest_DataObject();
+        $obj->MVField = ['Three', 'Four'];
+        $field->setValue('', $obj);
+        $this->assertEquals('Three,Four', $field->dataValue());
+    }
+}