查找具有特定属性的所有类

本文关键字：属性 查找 | 更新日期: 2023-09-27 17:55:00

可能重复：
查找具有特定属性的所有类

在程序集中，我希望获得特定类属性的所有实例。换句话说，我想要一个具有特定属性的类的列表。

通常，您会有一个类，可以使用GetCustomAttributes方法为其获取属性。

是否可以列出具有特定属性的人的列表？

查找具有特定属性的所有类

public static IEnumerable<Type> GetTypesWithMyAttribute(Assembly assembly)
{
    foreach(Type type in assembly.GetTypes())
    {
        if (Attribute.IsDefined(type, typeof(MyAttribute)))
            yield return type;
    }
}

或者：

public static List<Type> GetTypesWithMyAttribute(Assembly assembly)
{
    List<Type> types = new List<Type>();
    foreach(Type type in assembly.GetTypes())
    {
        if (type.GetCustomAttributes(typeof(MyAttribute), true).Length > 0)
            types.Add(type);
    }
    return types;
}

Linq VS我的方法基准(100000次迭代(：

Round 1
My Approach:     2088ms
Linq Approach 1: 7469ms
Linq Approach 2: 2514ms
Round 2
My Approach:     2055ms
Linq Approach 1: 7082ms
Linq Approach 2: 2149ms
Round 3
My Approach:     2058ms
Linq Approach 1: 7001ms
Linq Approach 2: 2249ms

基准代码：

[STAThread]
public static void Main()
{
    List<Type> list;
    Stopwatch watch = Stopwatch.StartNew();
    for (Int32 i = 0; i < 100000; ++i)
        list = GetTypesWithMyAttribute(Assembly.GetExecutingAssembly());
    watch.Stop();
    Console.WriteLine("ForEach: " + watch.ElapsedMilliseconds);
    watch.Restart();
    for (Int32 i = 0; i < 100000; ++i)
        list = GetTypesWithMyAttributeLinq1(Assembly.GetExecutingAssembly());
    Console.WriteLine("Linq 1: " + watch.ElapsedMilliseconds);
    watch.Restart();
    for (Int32 i = 0; i < 100000; ++i)
        list = GetTypesWithMyAttributeLinq2(Assembly.GetExecutingAssembly());
    Console.WriteLine("Linq 2: " + watch.ElapsedMilliseconds);
    Console.Read();
}
public static List<Type> GetTypesWithMyAttribute(Assembly assembly)
{
    List<Type> types = new List<Type>();
    foreach (Type type in assembly.GetTypes())
    {
        if (Attribute.IsDefined(type, typeof(MyAttribute)))
            types.Add(type);
    }
    return types;
}
public static List<Type> GetTypesWithMyAttributeLinq1(Assembly assembly)
{
    return assembly.GetTypes()
               .Where(t => t.GetCustomAttributes().Any(a => a is MyAttribute))
               .ToList();
}
public static List<Type> GetTypesWithMyAttributeLinq2(Assembly assembly)
{
    return assembly.GetTypes()
               .Where(t => Attribute.IsDefined(t, typeof(MyAttribute)))
               .ToList();
}

您可以使用反射来完成此操作。这将为您获得当前程序集中具有MyAttribute的所有类型的List<Type>。

using System.Linq;
using System.Reflection;
// ...
var asmbly = Assembly.GetExecutingAssembly();
var typeList = asmbly.GetTypes().Where(
        t => t.GetCustomAttributes(typeof (MyAttribute), true).Length > 0
).ToList();

var list = asm.GetTypes()
            .Where(t => t.GetCustomAttributes().Any(a => a is YourAttribute))
            .ToList();

如果没有代码示例，我们假设您有一个List<Type>或Assembly。

public List<Type> TypesWithAttributeDefined(Type attribute)
{
  List<Type> types = assembly.GetTypes();
  return types.Where(t => Attribute.IsDefined(t, attribute)).ToList();
}
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