C#枚举高级应用

我们经常使用枚举，但是可能只是一些简单的应用，其实在我们的项目中用到的 下拉列表、Model属性类型等，都可以利用枚举更好的实现。

//定义枚举

public enum DepartmentEum    {        [Description("第一产品事业部")]        FirstDept = 1

}

1、下拉列表使用枚举数据源：

//绑定部门
var deptList = EnumHelper.GetCachedDictionary(typeof(DepartmentEum ));
var ddlDeptList = new List<SelectListItem>();
ddlDeptList.Add(new SelectListItem() { Text = "请选择", Value = "-1" });
foreach (var item in deptList)
{
ddlDeptList.Add(new SelectListItem() { Text = item.Value, Value = item.Key });
}

2、Model属性类型：

/// <summary>
/// 部门枚举
/// </summary>
[DataMember]
public DepartmentEum Department { get; set; }

//获取枚举值

(int)model.Department

//获取枚举描述信息

EnumHelper.GetEnumDescription(model.Department)

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

3、以下是枚举帮助类

EnumHelper.cs
public static class EnumHelper
{
private static readonly Hashtable ht = Hashtable.Synchronized(new Hashtable());  /// <summary>
/// 从缓存中获取枚举对应的List
/// </summary>
/// <param name="type"></param>
/// <returns></returns>
public static IList<KeyValuePair<string, string>> GetCachedDictionary(Type type)
{
if (ht.Contains(type))
{
return ht[type] as IList<KeyValuePair<string, string>>;
}
else
{
IList<KeyValuePair<string, string>> dict = GetDictionary(type);
ht[type] = dict;
return dict;
}
}  public static IList<KeyValuePair<string, string>> GetDictionary(Type type)
{
if (!type.IsEnum)
{
throw new InvalidOperationException("错误的枚举类型");
}
FieldInfo[] fields = type.GetFields();
IList<KeyValuePair<string, string>> dict = new List<KeyValuePair<string, string>>();
foreach (var item in fields)
{
if (item.FieldType.IsEnum == false) { continue; }
string desription = string.Empty;
object[] objs = item.GetCustomAttributes(typeof (DescriptionAttribute), false);
if (objs != null && objs.Length> 0)
{
DescriptionAttribute da = (DescriptionAttribute) objs[0];
desription = da.Description;
}
else
{
desription = item.Name;
}
dict.Add(new KeyValuePair<string, string>(((int) Enum.Parse(type, item.Name)).ToString(), desription));
}
return dict;
}  public static string GetCachedDescription(Type type, string fieldName)
{
IList<KeyValuePair<string, string>> dictionary = GetCachedDictionary(type);
foreach (KeyValuePair<string, string> keyValuePair in dictionary)
{
if (keyValuePair.Key == ((int) (Enum.Parse(type, fieldName))).ToString())
{
return keyValuePair.Value;
}
}
return fieldName;
}  public static string GetCachedFieldName(Type type, string description)
{
IList<KeyValuePair<string, string>> dictionary = GetCachedDictionary(type);
foreach (KeyValuePair<string, string> keyValuePair in dictionary)
{
if(keyValuePair.Value == description)
{
return keyValuePair.Key;
}
}
return description;
}        ///<summary>
/// 根据枚举类型获取描述
///</summary>
///<param name="enumSubitem">类型</param>
///<returns>描述</returns>
public static string GetEnumDescription(Enum value)
{
// Get the Description attribute value for the enum value
FieldInfo fi = value.GetType().GetField(value.ToString());
DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
if (attributes.Length > 0)
{
return attributes[0].Description;
}
else
{
return value.ToString();
}
}        /// <summary>
/// 从缓存中获取枚举对应的List[添加一空白列]
/// </summary>
/// <param name="type"></param>
/// <returns></returns>
public static IList<KeyValuePair<string, string>> GetCachedDictionaryBlank(Type type)
{
if (ht.Contains(type))
{
return ht[type] as IList<KeyValuePair<string, string>>;
}
IList<KeyValuePair<string, string>> dict = GetDictionary(type);
dict.Insert(0, new KeyValuePair<string, string>((-1).ToString(), string.Empty));
ht[type] = dict;
return dict;
}        public static KeyValuePair<string, string> GetEnum(Type type, string fieldName)
{
KeyValuePair<string, string> kvp = new KeyValuePair<string, string>();
IList<KeyValuePair<string, string>> dictionary = GetCachedDictionary(type);
foreach (KeyValuePair<string, string> keyValuePair in dictionary)
{
if (keyValuePair.Key == ((int)(Enum.Parse(type, fieldName))).ToString())
{
kvp = keyValuePair;
break;
}
}
return kvp;
}
}