private bool HasEmptySelectListItem(IReadonlyFieldConfiguration fieldConfiguration)
{
if (fieldConfiguration.EmptyItemHidden)
{
return(false);
}
// If it's a checkbox list then it
// shouldn't since you can uncheck everything
if (fieldConfiguration.DisplayType == FieldDisplayType.List && FieldGenerator.HasMultipleValues())
{
return(false);
}
// If it's a radio list for a required field then it
// shouldn't since no value is not a valid value and
// an initial null value translates to none of the radio
// boxes being selected
if (fieldConfiguration.DisplayType == FieldDisplayType.List)
{
return(!FieldGenerator.Metadata.IsRequired);
}
// If it's a multi-select dropdown and required then
// there shouldn't be an empty item
if (FieldGenerator.HasMultipleValues())
{
return(!FieldGenerator.Metadata.IsRequired);
}
// Dropdown lists for nullable types should have an empty item
if (!FieldGenerator.Metadata.ModelType.IsValueType ||
Nullable.GetUnderlyingType(FieldGenerator.Metadata.ModelType) != null)
{
return(true);
}
return(false);
}