FeedCenter/Application/MainWindow/DragDrop.cs

using System;
using System.Linq;
using System.Net;
using System.Windows;

namespace FeedCenter
{
    public partial class MainWindow
    {
        private readonly string[] _chromeExtensions = { "chrome-extension://ehojfdcmnajoklleckniaifaijfnkpbi/subscribe.html?", "chrome-extension://nlbjncdgjeocebhnmkbbbdekmmmcbfjd/subscribe.html?" };

        private void HandleDragOver(object sender, DragEventArgs e)
        {
            // Default to not allowed
            e.Effects = DragDropEffects.None;
            e.Handled = true;

            // If there isn't any text in the data then it is not allowed
            if (!e.Data.GetDataPresent(DataFormats.Text))
                return;

            // Get the data as a string
            var data = (string) e.Data.GetData(DataFormats.Text);

            // If the data doesn't look like a URI then it is not allowed
            if (!Uri.IsWellFormedUriString(data, UriKind.Absolute))
                return;

            // Allowed
            e.Effects = DragDropEffects.Copy;
        }

        private void HandleDragDrop(object sender, DragEventArgs e)
        {
            // Get the data as a string
            var data = (string) e.Data.GetData(DataFormats.Text);

            if (string.IsNullOrEmpty(data))
                return;

            // Check to see if the data starts with any known Chrome extension
            var chromeExtension = _chromeExtensions.FirstOrDefault(data.StartsWith);

            // Remove the Chrome extension URL and decode the URL
            if (chromeExtension != null)
            {
                data = data[chromeExtension.Length..];
                data = WebUtility.UrlDecode(data);
            }

            // Handle the new feed but allow the drag/drop to complete
            Dispatcher.BeginInvoke(new NewFeedDelegate(HandleNewFeed), data);
        }
    }
}