C＃ - 條件列表中的動態linq

Question

我有兩節課：

public class Customer
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public List<Product> Product { get; set; }
}

public class Product
{
    public string ProductNumber { get; set; }

    public string ProductColor { get; set; }
}

還有一個例子：

Customer[] c = new Customer[]
{
    new Customer()
    {
        FirstName = "FirstName1",
        LastName = "LastName1",
        Product = new List<Product>
        {
            new Product()
            {
                ProductColor = "ProductColor1",
                ProductNumber = "11"
            }
        }
    },
    new Customer()
    {
        FirstName = "FirstName2",
        LastName = "LastName2",
        Product = new List<Product>
        {
            new Product()
            {
                ProductColor = "ProductColor2",
                ProductNumber = "12"
            }
        }
    }
};

我使用System.Dynamic.Linq庫來過濾我的數組：

var filter = c.Where("FirstName == \\"FirstName1\\"").Select(x => x).ToList();

我創建了一個類condition和一個實例：

public class condition
{
    public string propertyName { get; set; }

    public string  propertyValue { get; set; }
}

List<condition> f = new List<condition>
{
   new condition()
   {
       propertyName = "FirstName",
       propertyValue = "FirstName1"
   },
   new condition()
   {
       propertyName = "Product.ProductColor",
       propertyValue = "11"
   }
};

我想從這個List<Condition>創建多個子句Where

這個怎么做 ？

Answer 1

從我可以收集到的只是一個簡單的例子，你的名單上執行此操作？ 除非我錯過了什么？

 var query = f.Where(x => x.propertyName == "FirstName" && x.propertyValue == "FirstName1");

Answer 2

為了解決你的問題，我修改了你的條件類，如下所示：

客戶的條件可能包含產品條件列表：

public class Condition
    {
        public string propertyName { get; set; }
        public string propertyValue { get; set; }
        public ICollection<Condition> Conditions { get; set; }
    }

要創建它：

  List<Condition> f = new List<Condition>
  {
    new Condition()
    {
      propertyName = "FirstName",
      propertyValue = "FirstName1",
      Conditions = new List<Condition>
      {
        new Condition
        {
          propertyName = "ProductColor",
          propertyValue = "11"
        }
      }
    },
  };

現在您可以使用以下查詢過濾客戶和具有給定條件的產品：

  var filteredCustomers =
              from condition in f
              from custmer in c
              from product in custmer.Product
              let propertyName = condition.propertyName
              let propertyValue = condition.propertyValue
              where (nameof(custmer.FirstName) == propertyName && custmer.FirstName == propertyValue)
                    &&
                    (condition.Conditions.Any(p => p.propertyName == nameof(product.ProductColor))
                    && condition.Conditions.Any(p => p.propertyValue == product.ProductNumber))
              select custmer;

            foreach (var filterCustmer in filteredCustomers.Distinct())
            {
                Console.WriteLine(filterCustmer.FirstName);
            }