MonoDroid Resource to FileSystem management

ResourceHelper.cs

using System;
using System.Collections.Generic;
using Android.Content.Res;
using System.Resources;
using System.IO;
using Android.Content;
using Android.App;

namespace AndroidSandbox
{
	public static class ResourceHelper 
	{
		private static Dictionary<string, string> _Hash = new Dictionary<string, string>();

		/// <summary>
		/// Takes in a resource name, and returns the SD card path that the file resides on.
		/// 
		/// If the file does not exist on the SD card, it will copy it over and add it to the 
		/// hash of known file locations.
		/// </summary>
		/// <returns>
		/// The path for resource.
		/// </returns>
		public static string GetPathForResource (this Activity activity, string resource)
		{
			if (_Hash.ContainsKey (resource))
				return _Hash [resource];
			else {
				var outDir = Path.Combine (Android.OS.Environment.ExternalStorageDirectory.AbsolutePath, resource);

				if(File.Exists (outDir)){
					_Hash.Add (resource, outDir);
					return outDir;
				}

				int resID = activity.Resources.GetIdentifier(resource , "raw", activity.PackageName);

				using (var input = activity.Resources.OpenRawResource(resID))
				using (StreamReader sr = new System.IO.StreamReader(input))
				using (StreamWriter sw = new StreamWriter(outDir))
				{
					sw.Write (sr.ReadToEnd());
				}

				_Hash.Add(resource, outDir);

				return outDir;
			}
		}

	}
}