如何遍历类的所有属性？

Question

我上课了.

Public Class Foo
    Private _Name As String
    Public Property Name() As String
        Get
            Return _Name
        End Get
        Set(ByVal value As String)
            _Name = value
        End Set
    End Property

    Private _Age As String
    Public Property Age() As String
        Get
            Return _Age
        End Get
        Set(ByVal value As String)
            _Age = value
        End Set
    End Property

    Private _ContactNumber As String
    Public Property ContactNumber() As String
        Get
            Return _ContactNumber
        End Get
        Set(ByVal value As String)
            _ContactNumber = value
        End Set
    End Property


End Class

我想循环上面的类的属性.例如;

Public Sub DisplayAll(ByVal Someobject As Foo)
    For Each _Property As something In Someobject.Properties
        Console.WriteLine(_Property.Name & "=" & _Property.value)
    Next
End Sub

Answer 1

使用反射:

Type type = obj.GetType();
PropertyInfo[] properties = type.GetProperties();

foreach (PropertyInfo property in properties)
{
    Console.WriteLine("Name: " + property.Name + ", Value: " + property.GetValue(obj, null));
}

编辑:您还可以将BindingFlags值指定为type.GetProperties():

BindingFlags flags = BindingFlags.Public | BindingFlags.Instance;
PropertyInfo[] properties = type.GetProperties(flags);

这会将返回的属性限制为公共实例属性(不包括静态属性,受保护属性等).

您无需指定BindingFlags.GetProperty,在调用type.InvokeMember()以获取属性的值时使用它.

Answer 2

请注意,如果您正在谈论的对象具有自定义属性模型(例如DataRowView等DataTable),那么您需要使用TypeDescriptor; 好消息是这对于常规课程仍然可以正常工作(甚至可以比反思快得多):

foreach(PropertyDescriptor prop in TypeDescriptor.GetProperties(obj)) {
    Console.WriteLine("{0} = {1}", prop.Name, prop.GetValue(obj));
}

这也可以轻松访问TypeConverter格式化等内容:

    string fmt = prop.Converter.ConvertToString(prop.GetValue(obj));

Answer 3

Brannon给出的VB版C#:

Public Sub DisplayAll(ByVal Someobject As Foo)
    Dim _type As Type = Someobject.GetType()
    Dim properties() As PropertyInfo = _type.GetProperties()  'line 3
    For Each _property As PropertyInfo In properties
        Console.WriteLine("Name: " + _property.Name + ", Value: " + _property.GetValue(Someobject, Nothing))
    Next
End Sub

使用绑定标志而不是第3行

    Dim flags As BindingFlags = BindingFlags.Public Or BindingFlags.Instance
    Dim properties() As PropertyInfo = _type.GetProperties(flags)

Answer 4

反思非常"沉重"

也许尝试这个解决方案:// C#

if (item is IEnumerable) {
    foreach (object o in item as IEnumerable) {
            //do function
    }
} else {
    foreach (System.Reflection.PropertyInfo p in obj.GetType().GetProperties())      {
        if (p.CanRead) {
            Console.WriteLine("{0}: {1}", p.Name, p.GetValue(obj,  null)); //possible function
        }
    }
}

"VB.Net

  If TypeOf item Is IEnumerable Then

    For Each o As Object In TryCast(item, IEnumerable)
               'Do Function
     Next
  Else
    For Each p As System.Reflection.PropertyInfo In obj.GetType().GetProperties()
         If p.CanRead Then
               Console.WriteLine("{0}: {1}", p.Name, p.GetValue(obj, Nothing))  'possible function
          End If
      Next
  End If

反射速度减慢了方法调用的速度+/- 1000 x,如"日常事物的表现"中所示