using System; using System.Reflection; using System.Reflection.Emit; // Define the custom attribute class [AttributeUsage(AttributeTargets.Method)] class MyCustomAttribute : Attribute { public readonly int Value; public MyCustomAttribute(int value) { Value = value; } } // Create a dynamic method var dynamicMethod = new DynamicMethod("MyMethod", typeof(void), null); // Create the custom attribute instance var customAttribute = new MyCustomAttribute(42); // Define the custom attribute builder var attributeType = customAttribute.GetType(); var attributeCtor = attributeType.GetConstructor(new []{ typeof(int) }); var attributeParams = new object[] { customAttribute.Value }; var attributeBuilder = new CustomAttributeBuilder(attributeCtor, attributeParams); // Apply the custom attribute to the dynamic method dynamicMethod.SetCustomAttribute(attributeBuilder); // Invoke the dynamic method and check the custom attribute value var result = (MyCustomAttribute)dynamicMethod.GetCustomAttributes(false)[0]; Console.WriteLine(result.Value); // Output: 42In this example, we create a custom attribute called `MyCustomAttribute` that accepts a single integer value in its constructor. We then create a dynamic method using the `DynamicMethod` class. We create an instance of the custom attribute and use a `CustomAttributeBuilder` to attach it to the dynamic method. We then invoke the dynamic method and retrieve the custom attribute value to verify that it was attached successfully. This code uses a CustomAttributeBuilder from the System.Reflection.Emit namespace.