Compiler Error CS1016

Named attribute argument expected

Unnamed attribute arguments must appear before the named arguments.

Example

The following sample generates CS1016:

// CS1016.cs
using System;

[AttributeUsage(AttributeTargets.Class)]
public class HelpAttribute : Attribute
{
    public HelpAttribute(string url)   // url is a positional parameter
    {
        m_url = url;
    }

    public string Topic = null;      // Topic is a named parameter
    private string m_url = null;
}

[HelpAttribute(Topic="Samples", "http://intranet/inhouse")]   // CS1016
// try the following line instead
//[HelpAttribute("http://intranet/inhouse", Topic="Samples")]
public class MainClass
{
    public static void Main ()
    {
    }
}