The 'GetURL' method of the external file did not take into considerat…

…ion the URL (which has specific attributes such as expiration time) (#898)

dotnet/src/dotnetframework/GxClasses/Domain/GXFileIO.cs

@@ -585,7 +585,12 @@ public string AbsolutePath
 	private string URL
 	{
 		get {
-			return _provider == null ? String.Empty : _provider.GetUrl(_name, _fileTypeAtt, 0);
+			if (_provider == null)
+				return string.Empty;
+			else if (!string.IsNullOrEmpty(_url))
+				return _url;
+			else
+				return _provider.GetUrl(_name, _fileTypeAtt, 0);
 		}
 	}