HttpValueCollection和NameValueCollection

Question

HttpValueCollection和NameValueCollection有什么区别？

如果可能，请举例说明。

谢谢

Answer 1

NameValueCollection对键是区分大小写的，而HttpValueCollection不区分大小写。HttpValueCollection也是一个从NameValueCollection派生的内部类，你永远不应该在代码中直接使用它。HttpValueCollection的另一个属性是，当您将值添加到此集合中时，它会自动对值进行url编码。

下面是如何使用HttpValueCollection类：

class Program
{
    static void Main()
    {
        // returns an implementation of NameValueCollection
        // which in fact is HttpValueCollection
        var values = HttpUtility.ParseQueryString(string.Empty);
        values["param1"] = "v&=+alue1";
        values["param2"] = "value2";*

        // prints "param1=v%26%3d%2balue1&param2=value2"
        Console.WriteLine(values.ToString());
    }
}

Answer 2

在达林的回答中不明显的一点是，NameValueCollection没有覆盖ToString()方法，而HttpValueCollection覆盖了它。如果要将集合转换回查询字符串，这种特殊的属性和值的隐式URL编码使后者成为正确的选择。

public class Test
{
    public static void Main()
    {
        var httpValueCollection = HttpUtility.ParseQueryString(string.Empty);
        httpValueCollection["param1"] = "value1";
        httpValueCollection["param2"] = "value2";
        Console.WriteLine(httpValueCollection.ToString());

        var nameValueCollection = new NameValueCollection();
        nameValueCollection["param1"] = "value1";
        nameValueCollection["param2"] = "value2";
        Console.WriteLine(nameValueCollection.ToString());  
    }
}

输出：

param1=value1&param2=value2
System.Collections.Specialized.NameValueCollection