获取按名称分组的列表的所有组合

我有以下TestParam列表...这只是一个参数列表，用于确定查询的运行方式。在以下情况下，预期结果将针对不同参数的所有组合执行。因此，一个列表列表，其中 CustomerId 33 以及列表中的每个产品 ID ...

List<TestParam> testList = new List<TestParam>();
        testList.Add(new TestParam() { Name = "CustomerId", Value = "33" });
        testList.Add(new TestParam() { Name = "ProductId", Value = "1" });
        testList.Add(new TestParam() { Name = "ProductId", Value = "2" });
        testList.Add(new TestParam() { Name = "ProductId", Value = "3" });
        testList.Add(new TestParam() { Name = "ProductId", Value = "4" });
        testList.Add(new TestParam() { Name = "ProductId", Value = "5" });
        testList.Add(new TestParam() { Name = "ProductId", Value = "6" });
        testList.Add(new TestParam() { Name = "ProductId", Value = "7" });
        testList.Add(new TestParam() { Name = "ProductId", Value = "8" });

TestParam 是一个普通封装的参数类，具有名称和值...

public class TestParam
    {
        public string Name { get; set; }
        public string Value { get; set; }
    }

最终结果将是一个列表列表，具有 CustomerId 33，以及所有其他产品。如果我在 TestParam 列表中有不同的名称和值，将获得相同的结果（以上只是一个示例）。

下面的代码，最终有几个列表，具体取决于上面列表的组合......

   // First get a list of distinct unique param collections...
    List<string> distinctParameterNames = new List<string>();
    testList.GroupBy(x => x.Name).ForEach(paramName => {
        distinctParameterNames.Add(paramName.Key);
    });
    // Get counts
    List<int> combinationList = new List<int>();
    foreach (var x in distinctParameterNames) { 
        combinationList.Add(testList.Where(y=>y.Name == x).Count());
    }
    // Will contain 2 lists, one having all combinations of parameters named CustomerId, and another with ProductId combinations...
    List<List<TestParam>> parameterList = new List<List<TestParam>>();
    foreach (var x in distinctParameterNames) {
        // Loop 
        List<TestParam> parameter = new List<TestParam>();
        testList.Where(paramName => paramName.Name == x).ForEach(y =>
        {
            parameter.Add(new TestParam() { Name = y.Name, Value = y.Value });
        });
        parameterList.Add(parameter);
    }

这将是列表之间的交叉点，最终结果将是一个列表列表，每个列表将具有以下组合......所以运行将返回（在这种情况下）：

1. 客户 33，产品 ID 1
2. 客户 33，产品 ID 2
3. 客户 33，产品 ID 3
4. 客户 33，产品 ID 4
5. 客户 33，产品 ID 5
6. 客户 33，产品 ID 6
7. 客户 33，产品 ID 7
8. 客户 33，产品 ID 8

最有效和最通用的方法是什么？

public static List<List<T>> AllCombinationsOf<T>(params List<T>[] sets)
        {
            // need array bounds checking etc for production
            var combinations = new List<List<T>>();
            // prime the data
            foreach (var value in sets[0])
                combinations.Add(new List<T> { value });
            foreach (var set in sets.Skip(1))
                combinations = AddExtraSet(combinations, set);
            return combinations;
        }
        private static List<List<T>> AddExtraSet<T>
     (List<List<T>> combinations, List<T> set)
        {
            var newCombinations = from value in set
                                  from combination in combinations
                                  select new List<T>(combination) { value };
            return newCombinations.ToList();
        }

var intersection = AllCombinationsOf(parameterList.ToArray());

var customers = from a in testlist where a.name='customerid'
                select a;
var products = from a in testlist where a.name='productid'
                select a;  

for(var c in customers)
{
    loop products
     for(var p in products)
     {
        var customerproducts = new CustomerProducts{
            Customer = c.Name +' ' + c.Value
            Product = p.Name + ' ' + p.value
         };
       then add it into a list 
     }
}

        var groups = testList.GroupBy(_ => _.Name);
        IEnumerable<IEnumerable<TestParam>> result = null;
        foreach (var g in groups)
        {
            var current = g.Select(_ => new[] { _ });
            if (result == null)
            {
                result = current;
                continue;
            }
            result = result.Join(current, _ => true, _ => true, (actual, c) => actual.Concat(c));
        }
        // check result
        foreach (var i in result)
        {
            Console.WriteLine(string.Join(", ", i.Select(_ => string.Format("{0}-{1}", _.Name, _.Value))));
        }