IEnumerable Group 由用户指定的动态键列表

一篇关于根据用户指定的动态键列表对IEnumerable进行分组的文章。

csharp
public class Student
{
    public string Name { get; set; }
    public int Age { get; set; }
    public double Score { get; set; }
}
public class Program
{
    public static void Main(string[] args)
    {
        List students = new List()
        {
            new Student { Name = "Alice", Age = 18, Score = 90 },
            new Student { Name = "Bob", Age = 20, Score = 85 },
            new Student { Name = "Alice", Age = 19, Score = 92 },
            new Student { Name = "Bob", Age = 19, Score = 88 },
            new Student { Name = "Charlie", Age = 18, Score = 95 }
        };
        List dynamicKeys = new List() { "Name", "Age", "Score" };
        var groupedStudents = students.GroupByDynamicKeys(dynamicKeys);
        foreach (var group in groupedStudents)
        {
            Console.WriteLine($"Group Key: {group.Key}");
            foreach (var student in group)
            {
                Console.WriteLine($"Name: {student.Name}, Age: {student.Age}, Score: {student.Score}");
            }
            Console.WriteLine();
        }
    }
}
public static class IEnumerableExtensions
{
    public static IEnumerable> GroupByDynamicKeys(this IEnumerable source, IEnumerable dynamicKeys)
    {
        var parameter = Expression.Parameter(typeof(T), "x");
        var keySelectors = dynamicKeys.Select(key => Expression.PropertyOrField(parameter, key));
        var keySelector = Expression.Lambda>(Expression.NewArrayInit(typeof(object), keySelectors), parameter);
        return source.GroupBy(keySelector.Compile());
    }
}