Question

我需要获得班级中所有成员的类型。

    public class Order
    {
        public int OrderID { get; set; }
        public int EmployeeID { get; set; }
        public string CustomerID { get; set; }
        public DateTime OrderDate { get; set; }
        public bool Verified { get; set; }

        public Order(int orderId, int empId, string custId, DateTime orderDate, bool verify)
        {
            this.OrderID = orderId;
            this.EmployeeID = empId;
            this.CustomerID = custId;
            this.OrderDate = orderDate;
            this.Verified = verify;
        }
    }

和我通过List

添加的类的值

            List<dynamic> dy = new List<dynamic>();
            dy.Add(new { OrderID = 11, EmployeeID = 5, CustomerID = "ALFKI", OrderDate = new DateTime(2015,01, 10), Verified = true });
            dy.Add(new { OrderID = 12, EmployeeID = 4, CustomerID = "CDSAW", OrderDate = new DateTime(2015, 02, 12), Verified = true });
            dy.Add(new { OrderID = 13, EmployeeID = 6, CustomerID = "ASDFG", OrderDate = new DateTime(2015, 03, 13), Verified = true });
            dy.Add(new { OrderID = 14, EmployeeID = 3, CustomerID = "XSDAF", OrderDate = new DateTime(2015, 04, 14), Verified = false });
            dy.Add(new { OrderID = 15, EmployeeID = 2, CustomerID = "MNHSD", OrderDate = new DateTime(2015, 05, 15), Verified = true });
            dy.Add(new { OrderID = 16, EmployeeID = 1, CustomerID = "OKJHG", OrderDate = new DateTime(2015, 06, 16), Verified = false });
            return dy;

要获取字段类型，我尝试使用以下代码。

Type type = dataSource.GetElementType();
Type t = typeof(object);
t = type.GetProperty("OrderDate").PropertyType;

它抛出一个空表达式错误。

这里OrderDate是DateTime对象。

Type type = dataSource.GetType();

这一行返回System.object。

尝试获取OrderDate字段时。

type.GetProperty(filterString).PropertyType;

返回Null，如何解决此问题。

在线：https://dotnetfiddle.net/zTYJGU

Answer 1

首先，如果你想获得指定类型的所有字段和属性类型，你应该知道一些事情。

每个房产都拥有自己的支持领域。对于自动生成的属性public int MeProperty { get; set; }，支持字段的名称为<MeProperty>k__BackingField。

了解这一点，您应该考虑提取FieldInfo而不是PropertyInfo。

另一件事是你假设GetProperty方法甚至会提取隐藏的（private，protected等...）成员，这是完全错误的。它希望您使用BindingFlags枚举指定可访问性级别。

获得所有这些知识后，您可以使用以下方法提取属性的所有字段：

var fields = type.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);

之后，您可以枚举并获取字段类型：

var fieldTypes = fields.Select(f => f.FieldType);

现在，fieldTypes IEnumerable<Type>包含type字段中指定的每种字段类型。

真正的问题是你想要实现自动映射器，它从动态类型创建你定义的类型。为此，我建议您使用my answer on this question

中的解决方案

修改

使用此代码：

class Program { static void Main() { foreach(var field in typeof(Order).GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public)) { Console.WriteLine(field.Name); } } public class Order { public int OrderID { get; set; } public int EmployeeID { get; set; } public string CustomerID { get; set; } public DateTime OrderDate { get; set; } public bool Verified { get; set; } public Order(int orderId, int empId, string custId, DateTime orderDate, bool verify) { this.OrderID = orderId; this.EmployeeID = empId; this.CustomerID = custId; this.OrderDate = orderDate; this.Verified = verify; } } }

您应该具有相同的输出：

<OrderID>k__BackingField <EmployeeID>k__BackingField <CustomerID>k__BackingField <OrderDate>k__BackingField <Verified>k__BackingField

获取班级所有成员的类型

1 个答案: