What is the "Name=value" in [MyAttribute(Name=value)]

Question

I don't know what phrasing to use to google this.

Consider this attribute:

 [MyAttribute(MyOption=true,OtherOption=false)]

What is the Name=value part? And how can I implement it in my own custom attributes?

Answer 1

You can use this by declaring public instance (non-static) properties or fields:

[AttributeUsage(AttributeTargets.All)]
public class MyAttribute : Attribute
{
    public string TestValue { get; set; }
}

[My(TestValue = "Hello World!")]
public class MyClass{}

So it works almost like the object initializer syntax, but with () instead of {}.

---

If you provide a constructor with parameters for your attribute, you have to pass the parameters first:

[AttributeUsage(AttributeTargets.All)]
public class MyAttribute : Attribute
{
    public string TestValue { get; set; }

    public MyAttribute(int arg)
    {}
}

[My(42, TestValue = "Hello World!")]
public class MyClass{}