KeyedCollection字符串大小写不敏感

Question

尝试遵循文档,我无法使其工作.使用键字符串键入KeyedCollection.

如何在KeyedCollection中使字符串键不区分大小写？

在Dictionary上只能在ctor中传递StringComparer.OrdinalIgnoreCase.

private static WordDefKeyed wordDefKeyed = new WordDefKeyed(StringComparer.OrdinalIgnoreCase);   // this fails

public class WordDefKeyed : KeyedCollection<string, WordDef>
{
        // The parameterless constructor of the base class creates a 
        // KeyedCollection with an internal dictionary. For this code 
        // example, no other constructors are exposed.
        //
        public WordDefKeyed() : base() { }

        public WordDefKeyed(IEqualityComparer<string> comparer)
            : base(comparer)
        {
            // what do I do here???????
        }

        // This is the only method that absolutely must be overridden,
        // because without it the KeyedCollection cannot extract the
        // keys from the items. The input parameter type is the 
        // second generic type argument, in this case OrderItem, and 
        // the return value type is the first generic type argument,
        // in this case int.
        //
        protected override string GetKeyForItem(WordDef item)
        {
            // In this example, the key is the part number.
            return item.Word;
        }
}

private static Dictionary<string, int> stemDef = new Dictionary<string, int(StringComparer.OrdinalIgnoreCase);   // this works this is what I want for KeyedCollection

Answer 1

如果您希望WordDefKeyed默认情况下您的类型不区分大小写,那么您的默认无参数构造函数应该将IEqualityComparer<string>实例传递给它,如下所示:

public WordDefKeyed() : base(StringComparer.OrdinalIgnoreCase) { }

该StringComparer班有一些默认的IEqualityComparer<T>通常使用的取决于你存储数据的类型实现:

• StringComparer.Ordinal和StringComparer.OrdinalIgnoreCase-当你使用机器可读的字符串,而不是被输入或向用户显示的字符串使用.

• StringComparer.InvariantCulture和StringComparer.CultureInvariantIgnoreCase-当你使用,不会显示给用户界面字符串,但对文化敏感,可能是跨文化一样使用.

• StringComparer.CurrentCulture和StringComparer.CurrentCultureIgnoreCase- 用于特定于当前文化的字符串,例如当您收集用户输入时.

如果你需要StringComparer一个文化等一个比它是与当前的文化,那么你可以调用静态Create方法来创建StringComparer特定CultureInfo.