Access to the value of a Custom Attribute

Question

I\'ve got this custom attribute:

[AttributeUsage(AttributeTargets.Method, AllowMultiple=false, Inherited = true)]
class MethodTestingAttibute : Attribute
{           


        

Answer 1

With my custom attribute:

[AttributeUsage(AttributeTargets.Method)]
public class AttributeCustom : Attribute
{
    public string MyPropertyAttribute { get; private set; }

    public AttributeCustom(string myproperty)
    {
        this.MyPropertyAttribute = myproperty;
    }
}

I create a method for to get attribute with his values:

public static AttributeCustom GetAttributeCustom<T>(string method) where T : class
{
    try
    {
        return ((AttributeCustom)typeof(T).GetMethod(method).GetCustomAttributes(typeof(AttributeCustom), false).FirstOrDefault());
    }
    catch(SystemException)
    {
        return null;
    }
}

With a example class (must be not static because T is generic)

public class MyClass
{
    [AttributeCustom("value test attribute")])
    public void MyMethod() 
    {
        //...
    }
}

Usage:

var customAttribute = GetAttributeCustom<MyClass>("MyMethod");
if (customAttribute != null)
{
    Console.WriteLine(customAttribute.MyPropertyAttribute);
}

Answer 2

Cast the object to MethodTestingAttibute:

object actual = method.Invoke(obj, null);

MethodTestingAttibute attribute = (MethodTestingAttibute)method.GetCustomAttributes(typeof(MethodTestAttribute), true)[0];
string expected = attribute.Value;

bool areEqual = string.Equals(expected, actual != null ? actual.ToString() : null, StringComparison.Ordinal);

Answer 3

To get the value of an attribute property, just cast the object returned by GetCustomAttributes():

{
    string val;
    object[] atts = method.GetCustomAttributes(typeof(MethodTestAttibute), true);
    if (atts.Length > 0)
       val = (atts[0] as MethodTestingAttibute).Value;
}

Answer 4

var attribute =
   (MethodTestingAttibute)
   typeof (Vehicles)
      .GetMethod("m1")
      .GetCustomAttributes(typeof (MethodTestingAttibute), false).First();
Console.WriteLine(attribute.Value);

Answer 5

Please see the following link, it gets the attribute of an enum but you can customize is to get your custom attribute.

Getting attribute of Enum

Answer 6

Check the code here http://msdn.microsoft.com/en-us/library/bfwhbey7.aspx

Excerpt:

        // Get the AClass type to access its metadata.
        Type clsType = typeof(AClass);
        // Get the type information for Win32CallMethod.
        MethodInfo mInfo = clsType.GetMethod("Win32CallMethod");
        if (mInfo != null)
        {
            // Iterate through all the attributes of the method.
            foreach(Attribute attr in
                Attribute.GetCustomAttributes(mInfo)) {
                // Check for the Obsolete attribute.
                if (attr.GetType() == typeof(ObsoleteAttribute))
                {
                    Console.WriteLine("Method {0} is obsolete. " +
                        "The message is:",
                        mInfo.Name);
                    Console.WriteLine("  \"{0}\"",
                        ((ObsoleteAttribute)attr).Message);
                }

                // Check for the Unmanaged attribute.
                else if (attr.GetType() == typeof(UnmanagedAttribute))
                {
                    Console.WriteLine(
                        "This method calls unmanaged code.");
                    Console.WriteLine(
                        String.Format("The Unmanaged attribute type is {0}.",
                                      ((UnmanagedAttribute)attr).Win32Type));
                    AClass myCls = new AClass();
                    myCls.Win32CallMethod();
                }
            }
        }