SilverStripe DropdownField的默认值设置为空白

Question

有人可以帮助我在SilverStripe 3的DropdownField中将空白设置为默认值吗？

当前这是我的代码：

DropdownField::create(
    'HowHear',
    'How did you hear of this job?',
    array(
        'Indeed' => 'Indeed',
        'Caterer' => 'Caterer',
        'Gumtree' => 'Gumtree',
        'Word of mouth' => 'Word of mouth',
        'Other' => 'Other',
    )
)->addExtraClass('full-width'),

Answer 1

在SilverStripe 3和4中，DropdownField具有函数setEmptyString('')，该函数将设置默认的空字符串：

DropdownField::create(
    'HowHear',
    'How did you hear of this job?',
    [
        'Indeed' => 'Indeed',
        'Caterer' => 'Caterer',
        'Gumtree' => 'Gumtree',
        'Word of mouth' => 'Word of mouth',
        'Other' => 'Other',
    ]
)->addExtraClass('full-width')->setEmptyString('')