枚举的多语言显示

关于枚举类型的多语言显示，其实就是Globalization的问题。解决方案当然不止一种，这里介绍一种可用性和扩展性的比较好的通用方法。

显然这里自己去实现自定义格式化，即通过IFormatable、IFormatProvider、ICustomFormatter等接口已达到Globalization有点小题大作了，而另外一个很容易想到的点是通过DiaplayMember实现显示值得自定义（对于简单Binding，例如ComboBox、ListBox等只用重载ToString就可以了）。

首先，我们希望Binding整个枚举类型的每一个值，也就是说，我们需要把这个枚举的所有值变成一个数据源，为了实现这一点，我们可以使用Enum上的helper方法Enum.GetValues(Type)来返回一个对所有值得枚举，然后依次添加到IList对象或者IListSource接口即可。

if (!typeof(EnumType).IsEnum) { throw new NotSupportedException("Can not support type: " + typeof(EnumType).FullName); // It's better use resource version as below. // throw new NotSupportedException(SR.GetString("TYPE_NOT_SUPPORT", typeof(EnumType).FullName)); } // Use Enum helper enumerator list all enum values and add to current context. foreach (EnumType value in Enum.GetValues(typeof(EnumType))) { //TODO: add each value to IList base.Add(new EnumAdapter(value)); }

然后，取到了值，由于我们希望自定义Binding显示，那么需要对枚举值进行封装，而在这个封装里面，我们可以实现多语言的支持。

/// <summary> /// Enum value adapter, used to get values from each Cultures. /// </summary> public sealed class EnumAdapter { /**//// <summary> /// Storage the actual Enum value. /// </summary> private EnumType _value; /**//// <summary> /// Constructor an <see cref="EnumAdapter"/>. /// </summary> /// <param name="value">The enum value.</param> /// <exception cref=""> /// /// </exception> public EnumAdapter(EnumType value) { if (!Enum.IsDefined(typeof(EnumType), value)) { throw new ArgumentException(string.Format("{0} is not defined in {1}", value, typeof(EnumType).Name), "value"); // It's better use resource version as below. // throw new ArgumentException(SR.GetString("ENUM_NOT_DEFINED_FMT_KEY", value, typeof(EnumType).Name), "value"); } _value = value; } /**//// <summary> /// Gets the actual enum value. /// </summary> public EnumType Value { get { return _value; } } /**//// <summary> /// Gets the display value for enum value by search local resource with currrent UI lture /// and special key which is concated from Enum type name and Enum value name. /// </summary> /// <remarks> /// This would get correct display value by accessing location resource with current UI Culture. /// </remarks> public string DisplayValue { get { return SR.GetString(string.Format("{0}.{1}", typeof(EnumType).Name, _value.ToString())); } } //TODO: If you want more, please add below }

至此，整个功能的框架已经完成，下面我们来看看一些细节——如何对资源读取和管理的封装：

/// <summary> /// Constructor a new <see cref="SR"/>. /// </summary> internal SR() { //TODO: If you modified resource location, please update here this.resources = new System.Resources.ResourceManager( string.Concat(typeof(EnumAdapter).Namespace, ".Resource"), base.GetType().Assembly); } /**//// <summary> /// Get singleton instance. /// </summary> /// <returns>A singleton <see cref="SR"/></returns> private static SR GetLoader() { if (loader == null) { lock (SR.InternalSyncObject) { if (loader == null) { loader = new SR(); } } } return loader; } /**//// <summary> /// Gets an object from resources by special key, which provided by <paramref name="name"/>. /// </summary> /// <param name="name">Resource accessed key</param> /// <returns>return stored object in resource. if resource not found, return <paramref name="name"/> as object.</returns> public static object GetObject(string name) { SR loader = GetLoader(); if (loader == null) { return null; } try { return loader.resources.GetObject(name, Culture); } catch { } return name; } /**//// <summary> /// Gets a string from resources by special key, which provided by <paramref name="name"/>. /// </summary> /// <param name="name">Resource accessed key</param> /// <returns>return stored string in resource. If resource not found, retuen <paramref name="name"/> as result.</returns> public static string GetString(string name) { SR loader = GetLoader(); if (loader == null) { return null; } try { return loader.resources.GetString(name, Culture); } catch { } return name; } /**//// <summary> /// Gets a formatted string from resources by special key, which provided by <paramref name="name"/> and optional parameters. /// </summary> /// <param name="name">Resource accessed key</param> /// <param name="args">format arguments.</param> /// <returns>return stored string in resource. If resource not found, use <paramref name="name"/> as formator, return the formatted string.</retur public static string GetString(string name, params object[] args) { SR loader = GetLoader(); if (loader == null) { return null; } string format = name; try { format = loader.resources.GetString(name, Culture); } catch { } if ((args == null) || (args.Length <= 0)) { return format; } // It's better cut long arg for formating. for (int i = 0; i < args.Length; i++) { string arg = args[i] as string; if ((arg != null) && (arg.Length > 0x400)) { args[i] = arg.Substring(0, 0x3fd) + ""; } } return string.Format(System.Globalization.CultureInfo.CurrentCulture, format, args); }

OK，大功告成，有了这么一个封装，在应用里就可以简单的这么几句够搞定。

private void Form1_Load(object sender, EventArgs e) { this.comboBox1.DataSource = new EnumDataSource<Sex>(); this.comboBox1.DisplayMember = "DisplayValue"; this.comboBox1.ValueMember = "Value"; } public enum Sex { Male, Female }