Question

我想获得在类的每个字段上都带有属性Sync.Field的字段列表。该字段可以/不能具有Sync.Field

的属性

我一直在尝试以下操作，但是在获取每个字段的自定义属性时遇到困难。

FieldInfo[] fiClass = typClass.GetFields();

FieldInfo[] lst = fiClass
                   .Where(c => c.CustomAttribute().GetType() == typeOf(Sync.Field))
                   .ToList();

Answer 1

我有一个通用的收集类，它使用一个数据类来将SNMP表与数据类字段进行匹配。像JsonProperty一样，将反序列化的值匹配到属性。用同样的方式定义一个SNMPPropertyAttribute。该属性本身是

[AttributeUsage(AttributeTargets.Property, Inherited = false, AllowMultiple = false)]
  sealed class SNMPPropertyAttribute : Attribute
  {
    public SNMPPropertyAttribute(string propertyOID) => PropertyOID = new ObjectIdentifier(propertyOID);

    public ObjectIdentifier PropertyOID { get; }
  }

在表构造器中时，我正在根据属性制作数据字段及其OID的字典：

public SNMPTableEntity()
    {
      snmpPoperties = new Dictionary<ObjectIdentifier, PropertyInfo>();
      foreach (PropertyInfo myProperty in GetType().GetProperties(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public))
      {
        CustomAttributeData snmpAttribure = myProperty.CustomAttributes.Where(x => x.AttributeType == typeof(SNMPPropertyAttribute)).FirstOrDefault();
        if (snmpAttribure != null)
          snmpPoperties.Add(new ObjectIdentifier((string)snmpAttribure.ConstructorArguments[0].Value), myProperty);
      }
    }

它看起来与您要达到的目标相似，因此希望对您有所帮助。但是不同之处在于，我使用的是属性，而不是字段。不知道是否有很大的不同，但是...

有一个使用示例：

  public class InterfaceTableEntity : SNMPTableEntity
  {
    /// <summary>
    /// A unique value for each interface.  Its value ranges between 1 and the value of ifNumber.  The value for each interface must remain constant at least from one re-initialization of the entity's network management system to the next re- initialization.
    /// </summary>
    [SNMPProperty("1.3.6.1.2.1.2.2.1.1")]
    protected Integer32 ifIndex { get; set; }
    /// <summary>
    /// A textual string containing information about the interface.  This string should include the name of the manufacturer, the product name and the version of the hardware interface.
    /// </summary>
    [SNMPProperty("1.3.6.1.2.1.2.2.1.2")]
    protected OctetString ifDescr { get; set; }
    /// <summary>
    /// The type of interface, distinguished according to the physical/link protocol(s) immediately `below' the network layer in the protocol stack.
    /// </summary>
    [SNMPProperty("1.3.6.1.2.1.2.2.1.3")]
    protected Integer32 ifType { get; set; }
}

Answer 2

如果您具有FieldInfo，则可以使用以下代码获取其属性的实例：

var attr = fieldInfo.GetCustomAttributes().OfType<Sync.FieldAttribute>().SingleOrDefault();

请参阅我的example on DotNetFiddle。

类中字段的属性

2 个答案: