C＃反射检查属性

Question

我想查一个特定的运行时类型是否包含有特定属性的这样的特性：

public void Audit(MongoStorableObject oldVersion, MongoStorableObject newVersion) 
    { 
     if(oldVersion.GetType() != newVersion.GetType()) 
     { 
      throw new ArgumentException("Can't Audit versions of different Types"); 
     } 
     foreach(var i in oldVersion.GetType().GetProperties()) 
     { 
      //The statement in here is not valid, how can I achieve look up of a particular attribute 
      if (i.GetCustomAttributes().Contains<Attribute>(MongoDB.Bson.Serialization.Attributes.BsonIgnoreAttribute)) continue; 
      //else do some actual auditing work 
     } 
    } 

但声明是无效的，你能告诉我如何实现查找这样的属性的特定属性？谢谢，

更新：

我发现这个不使智能感知抱怨：

if (i.GetCustomAttributes((new MongoDB.Bson.Serialization.Attributes.BsonIgnoreAttribute()).GetType(),false).Length > 0) continue; 

但我还是不能肯定这将做什么，我想这一点。

Answer 1

变化：

if (i.GetCustomAttributes().Contains<Attribute>(MongoDB.Bson.Serialization.Attributes.BsonIgnoreAttribute)) continue; 

到

if (i.GetCustomAttributes().Any(x=> x is MongoDB.Bson.Serialization.Attributes.BsonIgnoreAttribute)) continue; 

修订：

public void Audit(MongoStorableObject oldVersion, MongoStorableObject newVersion) 
    { 
     if(oldVersion.GetType() != newVersion.GetType()) 
     { 
      throw new ArgumentException("Can't Audit versions of different Types"); 
     } 
     foreach(var i in oldVersion.GetType().GetProperties()) 
     { 
      //The statement in here is not valid, how can I achieve look up of a particular attribute 
      if (i.GetCustomAttributes().Any(x=> x is MongoDB.Bson.Serialization.Attributes.BsonIgnoreAttribute)) continue; 
      //else do some actual auditing work 
     } 
    } 

澄清：

GetCustomAttributes（）返回属性上的属性对象列表。你需要遍历它们并检查它们的类型是否是BsonIgnoreAttribute。

Answer 2

private static void PrintAuthorInfo(System.Type t) 
{ 
    System.Console.WriteLine("Author information for {0}", t); 

    // Using reflection. 
    System.Attribute[] attrs = System.Attribute.GetCustomAttributes(t); // Reflection. 

    // Displaying output. 
    foreach (System.Attribute attr in attrs) 
    { 
     if (attr is Author) 
     { 
      Author a = (Author)attr; 
      System.Console.WriteLine(" {0}, version {1:f}", a.GetName(), a.version); 
     } 
    } 
} 

http://msdn.microsoft.com/en-us/library/z919e8tw.aspx