possible null assignment in Dictionary Contains Key

[bindaden]

Getting a warning on "!redirectsDictionary.ContainsKey(autoRedirect.Key)"asp.net possible null assignment to entity marked with "notnull" attribute.Just wondering what that's about ?\[code\]private static readonly Dictionary<string, Redirect> AutoRedirectsDictionary = new Dictionary<string, Redirect>();foreach (var r in db.SelectItems("fast:/sitecore/content/Redirects Root//*[@@templatename='Auto Redirect']")) { GenerateRedirects(Context.Database.GetItem(r.Fields["Root Node"].Value), r["URL Prefix"]); foreach (var autoRedirect in AutoRedirectsDictionary) { if (!string.IsNullOrEmpty(autoRedirect.Key) & !redirectsDictionary.ContainsKey(autoRedirect.Key)) { //Add to dictionary redirectsDictionary.Add(autoRedirect.Key, autoRedirect.Value); } } }public static void GenerateRedirects(Item redirectFolder, string urlPrefix) { if (redirectFolder == null) return; var childList = redirectFolder.GetChildren(); foreach (Item child in childList) { if (Utilities.HasFieldValue(child, FieldToFind)) { var shortcutUrl = urlPrefix + child.Fields[FieldToFind].Value.ToLower(); if (!string.IsNullOrEmpty(shortcutUrl) && !AutoRedirectsDictionary.ContainsKey(shortcutUrl)) { AutoRedirectsDictionary.Add(shortcutUrl, new Redirect(String.Empty, child, true)); } } else { GenerateRedirects(child, urlPrefix); } } }\[/code\]