Can anyone please explain to me a very basic example of a custom attribute with code?
You start by writing a class that derives from Attribute:
public class MyCustomAttribute: Attribute
{
public string SomeProperty { get; set; }
}
Then you could decorate anything (class, method, property, ...) with this attribute:
[MyCustomAttribute(SomeProperty = "foo bar")]
public class Foo
{
}
and finally you would use reflection to fetch it:
var customAttributes = (MyCustomAttribute[])typeof(Foo).GetCustomAttributes(typeof(MyCustomAttribute), true);
if (customAttributes.Length > 0)
{
var myAttribute = customAttributes[0];
string value = myAttribute.SomeProperty;
// TODO: Do something with the value
}
You could limit the target types to which this custom attribute could be applied using the AttributeUsage attribute:
/// <summary>
/// This attribute can only be applied to classes
/// </summary>
[AttributeUsage(AttributeTargets.Class)]
public class MyCustomAttribute : Attribute
Important things to know about attributes: