Marc 的回答给出了不能直接注入 Grid 的稀疏矩阵。
我尝试从Vasu 提供的链接中扩展代码,如下所示:
public static Dictionary<TKey1, Dictionary<TKey2, TValue>> Pivot3<TSource, TKey1, TKey2, TValue>(
this IEnumerable<TSource> source
, Func<TSource, TKey1> key1Selector
, Func<TSource, TKey2> key2Selector
, Func<IEnumerable<TSource>, TValue> aggregate)
{
return source.GroupBy(key1Selector).Select(
x => new
{
X = x.Key,
Y = source.GroupBy(key2Selector).Select(
z => new
{
Z = z.Key,
V = aggregate(from item in source
where key1Selector(item).Equals(x.Key)
&& key2Selector(item).Equals(z.Key)
select item
)
}
).ToDictionary(e => e.Z, o => o.V)
}
).ToDictionary(e => e.X, o => o.Y);
}
internal class Employee
{
public string Name { get; set; }
public string Department { get; set; }
public string Function { get; set; }
public decimal Salary { get; set; }
}
public void TestLinqExtenions()
{
var l = new List<Employee>() {
new Employee() { Name = "Fons", Department = "R&D", Function = "Trainer", Salary = 2000 },
new Employee() { Name = "Jim", Department = "R&D", Function = "Trainer", Salary = 3000 },
new Employee() { Name = "Ellen", Department = "Dev", Function = "Developer", Salary = 4000 },
new Employee() { Name = "Mike", Department = "Dev", Function = "Consultant", Salary = 5000 },
new Employee() { Name = "Jack", Department = "R&D", Function = "Developer", Salary = 6000 },
new Employee() { Name = "Demy", Department = "Dev", Function = "Consultant", Salary = 2000 }};
var result5 = l.Pivot3(emp => emp.Department, emp2 => emp2.Function, lst => lst.Sum(emp => emp.Salary));
var result6 = l.Pivot3(emp => emp.Function, emp2 => emp2.Department, lst => lst.Count());
}
* 不能说任何关于性能的事情。