ConfigurationManager & Static Class

Question

I would like to use ConfigurationManager to access some string values from a static class. However, I need to handle specifically the absence of a valu

Answer 1

This just came up in a code review. The answers provided are great for strings. But they don't work for an int or a double, etc... Today, I needed to do this for a retry count and it needs to be an int.

So here is an answer for those who want Type conversion included.

Use this extension method:

using System.Collections.Specialized;
using System.ComponentModel;

namespace Rhyous.Config.Extensions
{
    public static class NameValueCollectionExtensions
    {
        public static T Get(this NameValueCollection collection, string key, T defaultValue)
        {
            var value = collection[key];
            var converter = TypeDescriptor.GetConverter(typeof(T));
            if (string.IsNullOrWhiteSpace(value) || !converter.IsValid(value))
            {
                return defaultValue;
            }

            return (T)(converter.ConvertFromInvariantString(value));
        }
    }
}

I also have unit tests for it, which you can find here: http://www.rhyous.com/2015/12/02/how-to-easily-access-a-web-config-appsettings-value-with-a-type-and-a-default-value

Hope that helps the next guy.