/// <summary>
/// Returns a select list for the given <paramref name="metadata"/>.
/// </summary>
/// <param name="metadata"><see cref="ModelMetadata"/> to generate a select list for.</param>
/// <returns>
/// An <see cref="IEnumerable{SelectListItem}"/> containing the select list for the given
/// <paramref name="metadata"/>.
/// </returns>
/// <exception cref="ArgumentException">
/// Thrown if <paramref name="metadata"/>'s <see cref="ModelMetadata.ModelType"/> is not an <see cref="Enum"/>
/// or if it has a <see cref="FlagsAttribute"/>.
/// </exception>
protected virtual IEnumerable <SelectListItem> GetEnumSelectList(ModelMetadata metadata)
{
if (metadata == null)
{
throw new ArgumentNullException(nameof(metadata));
}
if (!metadata.IsEnum || metadata.IsFlagsEnum)
{
var message = Resources.FormatHtmlHelper_TypeNotSupported_ForGetEnumSelectList(
metadata.ModelType.FullName,
nameof(Enum).ToLowerInvariant(),
nameof(FlagsAttribute));
throw new ArgumentException(message, nameof(metadata));
}
var selectList = new List <SelectListItem>();
foreach (var keyValuePair in metadata.EnumDisplayNamesAndValues)
{
var selectListItem = new SelectListItem
{
Text = keyValuePair.Key,
Value = keyValuePair.Value,
};
selectList.Add(selectListItem);
}
return(selectList);
}
/// <inheritdoc />
public IEnumerable <SelectListItem> GetEnumSelectList <TEnum>() where TEnum : struct
{
var type = typeof(TEnum);
var metadata = MetadataProvider.GetMetadataForType(type);
if (!metadata.IsEnum || metadata.IsFlagsEnum)
{
var message = Resources.FormatHtmlHelper_TypeNotSupported_ForGetEnumSelectList(
type.FullName,
nameof(Enum).ToLowerInvariant(),
nameof(FlagsAttribute));
throw new ArgumentException(message, nameof(TEnum));
}
return(GetEnumSelectList(metadata));
}
/// <summary>
/// Returns a select list for the given <paramref name="metadata"/>.
/// </summary>
/// <param name="metadata"><see cref="ModelMetadata"/> to generate a select list for.</param>
/// <returns>
/// An <see cref="IEnumerable{SelectListItem}"/> containing the select list for the given
/// <paramref name="metadata"/>.
/// </returns>
/// <exception cref="ArgumentException">
/// Thrown if <paramref name="metadata"/>'s <see cref="ModelMetadata.ModelType"/> is not an <see cref="Enum"/>
/// or if it has a <see cref="FlagsAttribute"/>.
/// </exception>
protected virtual IEnumerable <SelectListItem> GetEnumSelectList(ModelMetadata metadata)
{
if (metadata == null)
{
throw new ArgumentNullException(nameof(metadata));
}
if (!metadata.IsEnum || metadata.IsFlagsEnum)
{
var message = Resources.FormatHtmlHelper_TypeNotSupported_ForGetEnumSelectList(
metadata.ModelType.FullName,
nameof(Enum).ToLowerInvariant(),
nameof(FlagsAttribute));
throw new ArgumentException(message, nameof(metadata));
}
var selectList = new List <SelectListItem>();
var groupList = new Dictionary <string, SelectListGroup>();
foreach (var keyValuePair in metadata.EnumGroupedDisplayNamesAndValues)
{
var selectListItem = new SelectListItem
{
Text = keyValuePair.Key.Name,
Value = keyValuePair.Value,
};
if (!string.IsNullOrEmpty(keyValuePair.Key.Group))
{
if (!groupList.ContainsKey(keyValuePair.Key.Group))
{
groupList[keyValuePair.Key.Group] = new SelectListGroup()
{
Name = keyValuePair.Key.Group
};
}
selectListItem.Group = groupList[keyValuePair.Key.Group];
}
selectList.Add(selectListItem);
}
return(selectList);
}
/// <inheritdoc />
public IEnumerable <SelectListItem> GetEnumSelectList(Type enumType)
{
if (enumType == null)
{
throw new ArgumentNullException(nameof(enumType));
}
var metadata = MetadataProvider.GetMetadataForType(enumType);
if (!metadata.IsEnum || metadata.IsFlagsEnum)
{
var message = Resources.FormatHtmlHelper_TypeNotSupported_ForGetEnumSelectList(
enumType.FullName,
nameof(Enum).ToLowerInvariant(),
nameof(FlagsAttribute));
throw new ArgumentException(message, nameof(enumType));
}
return(GetEnumSelectList(metadata));
}
