[英]How to make dictionary extension-methods?
I'm trying to write a Dictionary
extension that works independently of the data types of Key/Value.我正在尝试编写一个独立于键/值数据类型工作的
Dictionary
扩展。 I tried pass it by using the object
data type, assuming that it will works with any type.我尝试使用
object
数据类型传递它,假设它适用于任何类型。
My code:我的代码:
public static class DictionaryExtensionsClass
{
public static void AddFormat(this Dictionary< ?? unknow type/*object*/, ??unknow type/*object*/> Dic, ??unknow type/*object*/ Key, string str, params object[] arglist)
{
Dic.Add(Key, String.Format(str, arglist));
}
}
You just make the method generic:您只需使方法通用:
public static void AddFormat<TKey>(this Dictionary<TKey, string> dictionary,
TKey key,
string formatString,
params object[] argList)
{
dictionary.Add(key, string.Format(formatString, argList));
}
Note that it's only generic in the key type as the value would have to be string
(or potentially object
or an interface that string
implements, I guess) given that you're going to add a string value to it.请注意,它仅在键类型中是通用的,因为如果您要向其添加字符串值,则该值必须是
string
(或者可能是object
或string
实现的接口,我猜)。
Unfortunately you can't really express the constraint of "only allow value types where string
is a valid value" in a generic type constraint.不幸的是,您无法在泛型类型约束中真正表达“仅允许
string
为有效值的值类型”的约束。
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