如何遍历一个类的所有属性？

Question

我有课。

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

我想遍历上述类的属性。 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));
}

对于 Excel - 必须添加哪些工具/参考项才能访问 BindingFlags，因为列表中没有“System.Reflection”条目

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、受保护的属性等）。

您不需要指定BindingFlags.GetProperty，在调用type.InvokeMember() 时使用它来获取属性的值。

Answer 2

Brannon 给出的 C# VB 版本：

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

使用绑定标志代替第 3 行

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

Answer 3

注意，如果你说的对象有自定义属性模型（比如DataRowView等DataTable），那么你需要使用TypeDescriptor；好消息是这仍然适用于普通课程（甚至可以是much quicker than reflection）：

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

这还可以轻松访问TypeConverter 等内容以进行格式化：

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

Answer 4

反射很“重”

也许试试这个解决方案：

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

反射减慢方法调用速度的 +/- 1000 倍，如The Performance of Everyday Things 所示

Answer 5

private void ResetAllProperties()
    {
        Type type = this.GetType();
        PropertyInfo[] properties = (from c in type.GetProperties()
                                     where c.Name.StartsWith("Doc")
                                     select c).ToArray();
        foreach (PropertyInfo item in properties)
        {
            if (item.PropertyType.FullName == "System.String")
                item.SetValue(this, "", null);
        }
    }

我使用上面的代码块来重置我的网络用户控件对象中的所有字符串属性，这些属性的名称以“Doc”开头。

Answer 6

这是另一种方法，使用 LINQ lambda：

C#：

SomeObject.GetType().GetProperties().ToList().ForEach(x => Console.WriteLine($"{x.Name} = {x.GetValue(SomeObject, null)}"));

VB.NET：

SomeObject.GetType.GetProperties.ToList.ForEach(Sub(x) Console.WriteLine($"{x.Name} = {x.GetValue(SomeObject, Nothing)}"))

Answer 7

我就是这样做的。

foreach (var fi in typeof(CustomRoles).GetFields())
{
    var propertyName = fi.Name;
}