Making a class/function that works like 'class(type)' in a class library

OK, this may be hard to explain so forgive me if you don't understand any of it. I am porting some of my functions that were previously in classes in my main application into a class library so I can use them in any projects. I have literally just started this so the code might not be very complete but I have this so far:

namespace WeatherLink
{
    public class DataDownloader
    {
        public class MetOffice
        {
            public DataType DataType;
            public bool CacheData;
            public string CacheLocation;
            public string ApiKey;

            public string GetData()
            {
                string resource = "";

                if (DataType.Type == "VisibleObservation")
                {
                    string sourcePath = string.Format(Path.Combine(@"C:\Users\Henry\AppData\Local\WeatherLink\temp\runtime_cache\visibleObservation"));

                    if (!File.Exists(sourcePath))
                    {
                        string sourceImage = string.Format("http://datapoint.metoffice.gov.uk/public/data/layer/wxobs/SATELLITE_Visible_N_Section/png?TIME={0}Z&key={1}");
                        System.Drawing.Bitmap image = new Bitmap(Image.FromStream(System.Net.HttpWebRequest.Create(sourceImage).GetResponse().GetResponseStream()));
                        Bitmap bitmap = new Bitmap(640, 852);
                        using (Graphics graphics = Graphics.FromImage(bitmap))
                        {
                            graphics.DrawImage(image, new Point[] { new Point(0, 0), new Point(650, 0), new Point(0, 852) });
                            bitmap.Save(sourcePath);
                            resource = sourcePath;
                        }
                    }
                    else { resource = sourcePath; }
                    return resource;
                }

                return resource;
            }
        }

        public class EuMetSat
        {

        }
    }

    public class DataType
    {
        public string Type { get; set; }
    }
}

...and I call it like this:

DataDownloader.MetOffice MetOffice = new DataDownloader.MetOffice();
DataDownloader.EuMetSat EuMetSat = new DataDownloader.EuMetSat();

I want to know how I can change my code in the library so that I can call a DataDownloader like this:

DataDownloader dd = new DataDownloader(MetOffice);
DataDownloader dd = new DataDownloader(EuMetSat);

...So instead of calling it using all the levels of the namespace I want to call the DataDownloader and specify its type (either MetOffice or EuMetSat). How do I do this? Would I have to use methods instead of classes for the 2 types? Like when you initiate most variables, as an example an XmlDocument has brackets after it (new XmlDocument()) where you could specify something for it. How would I do this in my code (new DataDownloader(MetOffice))? I hope you understand what I am trying to do. Thank You

Tags: C#