为什么我不能在C#中定义一个case-insensitve Dictionary? [英] Why can't I define a case-insensitve Dictionary in C#?
问题描述
这个C#/ WPF代码:
This C#/WPF code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace TestDict28342343
{
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
Dictionary<string, string> variableNamesAndValues =
new Dictionary<string, string>(StringComparison.InvariantCultureIgnoreCase);
}
}
}
给我错误:
最好的重载方法匹配
'System.Collections.Generic.Dictionary .Dictionary(System.Collections.Generic.IDictionary)'
有一些无效的参数
The best overloaded method match for 'System.Collections.Generic.Dictionary.Dictionary(System.Collections.Generic.IDictionary)' has some invalid arguments
但是我发现这个代码示例 everywhere 如 这里 和 这里 。
Yet I find this code example everywhere such as here and here.
如何定义一个字典,其键是不区分大小写?
推荐答案
您正在尝试使用 StringComparison
,这是一个枚举。您应该使用 StringComparer.InvariantCultureIgnoreCase
代替 - 这是一个返回 StringComparer
,它实现 的IEqualityComparer<串GT;
。然后,您最终会调用 字典<,>
构造函数重载接受一个 IEqualityComparer< TKey>
,它可以用来检查相等性并生成哈希代码。
You're trying to using StringComparison
, which is an enum. You should be using StringComparer.InvariantCultureIgnoreCase
instead - that's a property returning a StringComparer
, which implements IEqualityComparer<string>
. You'll then end up calling the Dictionary<,>
constructor overload accepting an IEqualityComparer<TKey>
which it can use to check for equality and generate hash codes.
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