71 lines
2.2 KiB
C#
71 lines
2.2 KiB
C#
using JNPF.DependencyInjection;
|
|
|
|
namespace JNPF.Common.Security;
|
|
|
|
/// <summary>
|
|
/// 比较器辅助类，用于快速创建<see cref="IComparer{T}"/>接口的实例.
|
|
/// </summary>
|
|
/// <example>
|
|
/// var comparer1 = Comparison[Person].CreateComparer(p => p.ID); var comparer2 = Comparison[Person].CreateComparer(p => p.Name); var comparer3 = Comparison[Person].CreateComparer(p => p.Birthday.Year).
|
|
/// </example>
|
|
/// <typeparam name="T">要比较的类型.</typeparam>
|
|
[SuppressSniffer]
|
|
public static class ComparisonHelper<T>
|
|
{
|
|
/// <summary>
|
|
/// 创建指定对比委托<paramref name="keySelector"/>的实例.
|
|
/// </summary>
|
|
public static IComparer<T> CreateComparer<TV>(Func<T, TV> keySelector)
|
|
{
|
|
return new CommonComparer<TV>(keySelector);
|
|
}
|
|
|
|
/// <summary>
|
|
/// 创建指定对比委托<paramref name="keySelector"/>与结果二次比较器<paramref name="comparer"/>的实例
|
|
/// </summary>
|
|
public static IComparer<T> CreateComparer<TV>(Func<T, TV> keySelector, IComparer<TV> comparer)
|
|
{
|
|
return new CommonComparer<TV>(keySelector, comparer);
|
|
}
|
|
|
|
/// <summary>
|
|
/// 常见的比较器.
|
|
/// </summary>
|
|
/// <typeparam name="TV">要比较的类型.</typeparam>
|
|
private class CommonComparer<TV> : IComparer<T>
|
|
{
|
|
private readonly IComparer<TV> _comparer;
|
|
private readonly Func<T, TV> _keySelector;
|
|
|
|
/// <summary>
|
|
/// 构造函数.
|
|
/// </summary>
|
|
/// <param name="keySelector"></param>
|
|
/// <param name="comparer"></param>
|
|
public CommonComparer(Func<T, TV> keySelector, IComparer<TV> comparer)
|
|
{
|
|
_keySelector = keySelector;
|
|
_comparer = comparer;
|
|
}
|
|
|
|
/// <summary>
|
|
/// 构造函数.
|
|
/// </summary>
|
|
/// <param name="keySelector"></param>
|
|
public CommonComparer(Func<T, TV> keySelector)
|
|
: this(keySelector, Comparer<TV>.Default)
|
|
{
|
|
}
|
|
|
|
/// <summary>
|
|
/// 比较.
|
|
/// </summary>
|
|
/// <param name="x"></param>
|
|
/// <param name="y"></param>
|
|
/// <returns></returns>
|
|
public int Compare(T x, T y)
|
|
{
|
|
return _comparer.Compare(_keySelector(x), _keySelector(y));
|
|
}
|
|
}
|
|
} |