将参数传递给Func＆lt;＆gt;的最佳方法是什么？在C＃？

Question

我有以下代码：

public void Test(Request request, Func<IEnumerable<Building>> buildings)
{
   vm.Buildings = Helper.GenerateDropdownList(request.BuildingId,() => buildings());
}

我现在想要将另一个参数传递给buildings()回调

public void Test(Request request, Func<IEnumerable<Building>> buildings)
{
   var cityId = GetCity();
   vm.Buildings = Helper.GenerateDropdownList(request.BuildingId,() => buildings(cityId));
}

输入该参数的正确方法是什么？

Answer 1

您的buildings代表必须是Func<T, TResult>而不是Func<TResult>。

假设cityId是int：

public void Test(Request request, Func<int, IEnumerable<Building>> buildings)
{
   var cityId = GetCity();
   m.Buildings = Helper.GenerateDropdownList(request.BuildingId,
                                             () => buildings(cityId));
}